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The Story for Spring: Drought Relief Not Likely

richard.a.rivera — Mon, 01 Apr 2013 13:01:30 +0000

NOAA’s Climate Prediction Center released its Spring Outlook on March 21. The big story for the upcoming spring: relief for many drought-stricken areas of the United States is not likely.

The map above shows the drought outlook for March 21 through June 30, 2013. Areas where drought is likely to persist or worsen are shown in reddish-brown. Areas of tan indicate where drought is likely to see some improvement, and areas where drought is likely to improve and its impacts ease are shown in green. Yellow indicates places where drought conditions are likely to develop.

Although drought is expected to improve in parts of the Southeast, the western Great Lakes, and the northern Great Plains, it will likely continue to plague large parts of the south-central and southwestern United States—even expanding into parts of California, eastern Texas, and the Florida Peninsula. Some areas of the country, especially the south-central region, have experienced drought conditions for over a year. Across the Pacific, Hawaii is also experiencing varying levels of drought.

Many of these drought-stricken areas are also favored to experience above-average temperatures and below-average precipitation this spring, including the south-central and southwestern United States. The maps below show probabilities of above- or below-average temperature and precipitation in the United States for April through June 2013.

Locations that are likely to experience above or below average temperatures are shaded in red or blue; precipitation forecasts are shown in shades of green (well above average) and brown (well below average). Places in gray indicate areas where there is an “equal chance” forecast, which means above-, near-, or below-average temperature or precipitation are all equally likely.

In the case of these forecasts, “well above average” and “well below average” refer to temperature or precipitation in the upper or lower third of the range of climate conditions observed in an area from 1981-2010. The outlooks are more confident in some places than they are in others; the lines trace the boundaries of different levels of probability. In the video below, Deputy Director of the Climate Prediction Center, Mike Halpert, talks in more depth about the Spring 2013 Climate Outlook.

Only a small area of the continental U.S.—extending along the US-Canadian border from the Pacific Northwest and into Montana and North Dakota—is favored to see well below average temperatures. Large parts of the country have an “equal chance” precipitation forecast, but there is a tilt in the odds toward well above average precipitation in parts of the Midwest.

Maps by NOAA Climate.gov team, based on forecasts provided by the NOAA Climate Prediction Center. Reviewed by Mike Halpert, Climate Prediction Center.

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In Watching for El Niño and La Niña, NOAA Adapts to Global Warming

richard.a.rivera — Tue, 05 Feb 2013 20:37:47 +0000

No single climate phenomenon has more influence on year-to-year variation in average global temperature than the El Niño-Southern Oscillation (ENSO). When the central tropical Pacific Ocean is warmer than average (El Niño) or colder than average (La Niña), a cascade of atmospheric changes ensures that many parts of the globe feel the effects.

But here’s a problem to consider: if the ocean today is warmer than the long-term average, won’t it look like the tropical Pacific is in a permanent El Niño? Won’t La Niña—the cool phase—just disappear? Will we have to redefine the nature of these influential climate events?

It’s a problem that scientists at NOAA’s Climate Prediction Center, the branch of the agency responsible for monitoring and forecasting ENSO events, have been considering for many years. The solution they came up with doesn’t change the definition of El Niño and La Niña episodes, but they were forced to reconsider what counts as “average” temperature in the tropical Pacific.

Defining El Niño and La Niña
The ENSO-related temperature fluctuations in the tropical Pacific that have such far-reaching impacts on seasonal climates downstream aren’t about a specific temperature. Instead, they are about relative temperatures, one region being hotter or colder than usual, and the climate chaos that ensues when things aren’t “normal.”

NOAA’s operational definition of El Niño and La Niña conditions is pretty basic: seasonal temperatures of 0.5°C warmer (El Niño) or cooler (La Niña) than average in the central tropical Pacific. A “season” is any rolling 3-month average: December-January-February, January-February-March, and so on. The Climate Prediction Center keeps an online record of all the seasonal temperature anomalies back to 1950.

For real-time La Niña/El Niño tracking, NOAA watches for temperature anomalies in the central tropical Pacific (between 5° north and south latitude and 120° to 170° west longitude). Map by Climate.gov team, adapted from original by the NOAA Climate Prediction Center.

For La Niña or El Niño conditions to graduate to a full-blown episode, the temperature anomaly must last five consecutive, overlapping seasons. To allow rankings and comparisons of all historic ENSO events, these long-lived events are color-coded in the Climate Prediction Center’s online table: blue for La Niña, red for El Niño.

Since ENSO events are identified by temperatures that are warmer or cooler than average, the key question is: what’s average? Up until last year, Climate Prediction Center scientists used a 30-year average of the three most recent complete decades, updated in each new decade. So, in the 1990s, for example, they used the 1961-1990 average, and in the 2000s, they used the 1971-2000 average.

Whenever the time period for the average shifted, all the previous seasonal averages in the table of historic events were re-calculated using the new base period. The routine update was supposed to ensure that at any point in time, the relative strength of all El Niño and La Niña episodes identified in the table was consistent—a consistency that is important for research into the influence of these episodes on global and regional climate.

If the climate weren’t changing, the differences between any 30-year average would be very small, and the impacts on the apparent strength of historic El Niño and La Niña episodes would be negligible. But over the span of the past century, ocean temperatures have been getting warmer, which means that the baseline for detecting El Niño and La Niña has been shifting. (For the statistical nitty gritty, see the research article by L’Heureux, et al., at the bottom of the page.)

The average monthly temperatures in the central tropical Pacific have been increasing. This graph shows the new 30-year averages that NOAA is using to calculate the relative strength of historic El Niño and La Niña events. Graph adapted by Climate.gov team from original by the NOAA Climate Prediction Center.

The past three decades have been the warmest on record both globally and in the tropical Pacific. Compared to this new, warmer ocean, historic cold episodes look even colder, while historic warm episodes look weaker. Instead of providing consistency, updating the historic events was going to distort the ENSO climate record.

“We could picture a day not too far in the future,” explains Mike Halpert, Deputy Director at CPC, “when a weak El Niño episode from the past would wind up looking like a weak La Niña episode when compared to the more recent, warmer ocean temperatures.”

To deal with the reality of climate change, Climate Prediction Center scientists decided, after brainstorming with colleagues at the International Research Institute for Climate and Society, to start using fixed 30-year averages. Each five-year period in the historical record now has its own 30-year average centered on the first year in the period: the years 1950 to 1955 are compared to the 1936-1965 average, for example, while the years 1956-1960 are compared to 1941-1970.

This approach works smoothly up through the 1996-2000 period, which uses the 1981-2010 average. However, the 2001-2005 period will require the 1985-2015 base period, and 2006-2010 will need the average from 1991-2021.

Until those years are available, CPC will use the most recently calculated climatology, which, for now, is the 1981-2010 average. They will update the climatology every five years. The next update will be in 2016, at which point the average for calculating La Niña and El Niño for the current decade will shift to the 1985-2015 period.

La Niñas We Didn’t Know We Had
The change in the way the Climate Prediction Center calculates the Pacific’s average temperature has already shaken up a couple of items in the table of historic El Niño and La Niña events. The revisions confirm that it was time to make a change.

In the last version of the table, all the temperature anomalies were based on the 1971-2000 average, which was relatively cool compared to the past three decades. Against that background, some periods of cooler-than-average temperatures (from late 2005 to early 2006 and from late 2008 through early 2009) were not quite cold enough for long enough to qualify as an official La Niña episode.

However, the new strategy calls for the current decade to be compared to the 1981-2010 average—the three warmest decades on record. When NOAA scientists updated the table, the cool periods in 2005/2006 and 2008/2009 emerged as true La Niña episodes.

When scientists used the 1971-2000 average (top) for comparing the strength of historic ENSO events, the influence of long-term warming in the tropical Pacific made recent El Niño events seem stronger than they were and made La Niña events hard to detect. When scientists compared temperatures from the past decade to the warmer 1981-2010 average (bottom), two new La Niña events (un-shaded boxes) emerged from the record. Graphics adapted by Climate.gov team from originals (here and here) by the NOAA Climate Prediction Center.

The newly emerged 2006 and 2009 La Niñas mean that 2012—also a La Niña year—is no longer officially the “warmest La Niña year on record,” as the National Climatic Data Center initially concluded in early January. That record will now go down as a tie between 2006 and 2009, with 2012 coming in a close third.

References & Links
Description of changes to the Oceanic Niño Index
Climate Variability: Oceanic Niño Index
Cold and warm episodes by season
L’Heureux, M. L., Collins, D. C., & Hu, Z.-Z. (2012, March.). Linear trends in sea surface temperature of the tropical Pacific Ocean and implications for the El Niño-Southern Oscillation. Climate Dynamics, 1–14. doi:10.1007/s00382-012-1331-2

Reviewed by Michelle L’Heureux and Mike Halpert, NOAA Climate Prediction Center, and Jessica Blunden, National Climatic Data Center.

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Drought Impacts Continue to Pile Up

richard.a.rivera — Mon, 04 Feb 2013 17:16:53 +0000

Record-low hay stocks. Significant damage to house foundations. Ethanol and beef processing plants idled. Mandatory water restrictions. At least 25,000 dead pecan trees in one Texas county. Ski area employment down. The list of impacts from the U.S. drought seems endless.

This map shows drought status across the United States as of January 29, 2013. Rain and snow have improved the drought somewhat in parts of the Midwest, the Ohio Valley, and the Deep South in the past 6-12 weeks, but areas of exceptional drought—the most severe category of drought —remain across the Great Plains and Georgia, with broad areas of extreme and severe drought across the West and Southeast.

According to the U.S. Drought Monitor, an estimated 58 percent of the contiguous United States was in some level of drought as of January 29, with an additional 12 percent in the “Abnormally dry” category. Stream flow forecasts for many major western rivers, including the Colorado and the Rio Grande, are below normal.

Map by Climate.gov team, based on data from the U.S. Drought Monitor Program. Reviewed by Jake Crouch and Deke Arndt, National Climatic Data Center.

Links
U.S. Drought Monitor
National Drought Impacts Reporter
USDA Natural Resource Conservation Service Stream Flow Maps
North American Drought Monitor

Talking about the Arctic with NOAA Administrator Lubchenco

Rebecca.Lindsey — Thu, 06 Dec 2012 18:36:58 +0000

Shallow melt ponds on the surface of the consolidated sea ice pack in the Chukchi Sea in July 2011. Photo by Karen Frey.

Climate.gov’s Brian Kahn interviews NOAA Administrator Jane Lubchenco about connections between Arctic climate change and the rest of the world.

Why should people who don’t live in and will likely never visit the Arctic care about the dramatic melt this year, or the other climate shifts in the region?
What happens in the Arctic doesn’t stay in Arctic. What happens there often affects people around the world. Melting ice and glaciers in Greenland can contribute quite significantly to sea level rise, which affects people in coastal areas around the world.

The changing interactions between the ocean and the atmosphere can affect weather patterns in the United States and in Europe. The biological changes in the Arctic also matter to people living outside the region. For example, changes in Arctic ecosystems can, in turn, affect migration patterns of birds that go from the Arctic to places at much lower latitudes. This shows that the Arctic is not just a remote place that few will ever have the opportunity to visit. It affects us in tangible ways that matter.

Dr. Jane Lubchenco, Under Secretary of Commerce for Oceans and Atmosphere and Administrator of the National Oceanic and Atmospheric Administration.

Apart from that, for many people, the Arctic represents a place that is remote, strange and very special. With species from polar bears, to ice seals, to ice fish, to microscopic plants, it’s a very, very special place. Just knowing that the ecosystems are changing means a lot to people. In short, changes in the Arctic affect people directly, physically and emotionally.

This year’s record low Arctic sea ice extent could be classified as an extreme event, though not on the economic order of Sandy, for example. How do you ensure this contributes to the climate discussion that Sandy and other recent extreme events have sparked?
We are witnessing more extreme weather and climate-related events. Even as we seek to understand exactly what the causes and consequences are, knowing that they’re happening is important because it tells us we need to expect surprises, and that there are further changes we need to anticipate.

Changes that are underway in the Arctic affect weather patterns elsewhere. We just don’t quite know how to connect the dots just yet. Paying attention to the Arctic Report Card is important intellectually but also in helping us think about some of the changes we should be preparing for, just like Sandy and the 2012 drought.

What are areas of active research in the Arctic? How will they help further our understanding of the region and what’s happening to it?
There are a wealth of research activities underway in the Arctic. Scientists track the changes and understand them so we can better anticipate them in the future. They range from simple things like forecasting ice, which is a lot harder than you’d think, to changes in physical systems and how they’ll affect biological and ecological parts of the system. For example, one line of inquiry is how the shift in sea ice affects microscopic plants in the ocean and, in turn, the marine mammals and birds that rely on them.

In the whole climate system, one of the major areas of research is what the changes will be in terms of how much sunlight is reflected away from the Earth and what the consequences of that are. Since snow is white and mostly reflects sunlight while ocean water is dark and absorbs it, changes in the amount of snow and ice in the Arctic are incredibly important to understand because they affect the energy budget for the globe.

What’s one thing most people don’t know about Arctic research but would be surprised or intrigued to learn about?
Many people assume we have the same ability to forecast weather and abrupt changes in weather systems in the Arctic region [as we do in other regions]. However, we simply don’t have the same scope of observations systems or track record to understand what combinations of factors can cause changes in weather in the Arctic like we do in the Lower 48.

There are also changes that are surprising people who live in the Arctic itself. For example, I visited Barrow, Alaska, a few years ago. When I arrived, there were a number of kids and city officials watching the surf crashing on the shoreline. Having seen surf crash along the California coast, I thought, “What’s the big deal?”

They said they’ve never seen this before; there used to be sea ice that would dampen the waves from storms. With no sea ice, there was now a long fetch of open water. This meant waves could build up and result in very significant surf right up the shore, which is now a big cause of coastal erosion.

How can the Arctic Report Card help inform policymakers and the public?
A key role of science is to inform our understanding of what’s happening to the world around us and what the consequences of different choices we make might be. The reason there’s a big push for research in the Arctic is it’s changing so rapidly and it has such huge consequences for the rest of world; yet we don’t understand a lot of it. Getting a better handle on Arctic science and the ways it’s changing has an immediate benefit by informing decision-making.

I believe Arctic science should be accessible, relevant, and understandable to citizens as well as policymakers since the Arctic is such a special place; and it’s important for scientists to help share that information in ways that are just that.

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2012 Arctic Report Card

Rebecca.Lindsey — Wed, 05 Dec 2012 19:18:21 +0000

NOAA released the 2012 installment of the annual Arctic Report Card on December 5, 2012, as part of the American Geophysical Union’s fall meeting. You won’t find these graphics in the Report Card itself. This collection is a gallery of highlights based on the report’s major themes. It was developed by the NOAA Climate.gov team in cooperation with Arctic Report Card authors and other Arctic experts.

Melt pond “skylights” enable massive under-ice bloom in Arctic

Rebecca.Lindsey — Wed, 05 Dec 2012 19:09:06 +0000

For much of the winter, the land within the Arctic Circle receives little direct sunlight*, and most of the surface of the Arctic Ocean is capped by ice. Beneath the ice cover, phytoplankton—the microscopic, plant-like organisms that underpin the entire ocean food web—take a “long winter’s nap.”

When the Sun returns and the ice retreats, it’s like a cover being drawn off the roof of a greenhouse. Along the edge of the retreating ice cover, the surface water explodes with blooms of phytoplankton.

The pair of satellite images above show a bloom in the Chukchi Sea northwest of Alaska on July 10, 2011. The top image is like a digital photo, showing swirls of sea ice along the crumbling edge of the consolidated ice pack. The bottom image is based on satellite observations of reflected light in wavelengths that are especially sensitive to the presence of chlorophyll. (Phytoplankton use chlorophyll for photosynthesis, just like land plants.)

North of Wrangel Island, the sea ice has a dingy look. This may be from sediment, but its distance from shore and the fact that it is fringed on both sides by waters with extremely high levels of chlorophyll suggest that the ice is being discolored by algae and other phytoplankton.

According to Arctic oceanographer Karen Frey, the discoloration is consistent with an unusual phenomenon that she encountered while on a research cruise in the Chukchi Sea in the first part of July: a massive bloom of phytoplankton stretching up to 100 kilometers (62 miles) under the ice pack.

Historically, the ice in this area has been thick enough even in spring to keep the waters below in darkness, Frey says. In the past decade, though, the ice conditions have changed dramatically, with a thinner ice cover that is laced with shallow ponds of meltwater. The ponds act like skylights, allowing light to filter through and support phytoplankton blooms.

The images above are like a photo and its negative, showing what the ice looks like from above (left, taken from the deck of the U.S. Coast Guard Cutter Healy) and below (right, captured by a waterproof HD camera lowered through a hole in the ice.) The pair of photos below shows the dramatic difference in water color and clarity during the massive under-ice bloom.

According to Frey, the presence of this bloom isn’t just a “geewhiz” phenomenon. Previous satellite-based estimates of Arctic phytoplankton productivity have generally assumed that nothing much is happening under the consolidated ice pack. Preliminary estimates of the size of this bloom and the area of sea ice around the rest of the Arctic that is in similar, melt-ponded condition each summer suggest that Arctic phytoplankton productivity could be ten times higher than previously estimated.

Read more about Arctic Ocean ecology in the Marine Ecosystems chapter of the 2012 Arctic Report Card.

References
Arrigo, K. R., Perovich, D. K., Pickart, R. S., Brown, Z. W., Dijken, G. L. van, Lowry, K. E., … Swift, J. H. (2012). Massive Phytoplankton Blooms Under Arctic Sea Ice. Science, 336(6087), 1408–1408. doi:10.1126/science.1215065

Frey, K. E., Perovich, D. K., & Light, B. (2011). The spatial distribution of solar radiation under a melting Arctic sea ice cover. Geophysical Research Letters, 38(22), L22501. doi:10.1029/2011GL049421

Satellite images by Jesse Allen, NASA Earth Observatory team, based on Aqua MODIS data provided by the GSFC Ocean Color team. Photos courtesy Karen Frey, Clark University.

*Updated Dec. 10, 2012. Previous version stated that “After the solstice, the Sun never rises on the land in the Arctic Circle,” but didn’t explain that the polar darkness lasts only a few days at that latitude before polar “twilight” returns.

Less glitter: Greenland Ice Sheet continued to darken in summer 2012

Rebecca.Lindsey — Wed, 05 Dec 2012 19:08:46 +0000

On a sunny day, Greenland is an immense, glittering expanse of snow and ice. But in recent summers, satellites have been observing less “glitter” from the Northern Hemisphere’s largest ice expanse due to surface melt and other changes caused by warmer temperatures. The summer of 2012 found Greenland darker than it has been since ice-sheet-wide observations began in 2000.

Map by NOAA climate.gov team, based on NASA MODIS albedo data provided by Jason Box, The Ohio State University. Inset image from NASA MODIS Rapid Response Project.
large map | large photo-like image

The map above shows the percent of incoming sunlight Greenland reflected during June through August 2012 compared to the average of summers from 2000-2011. Blue indicates less sunlight reflected than average, with dark blue indicating nearly 20 percent less sunlight than average reflected back into space. The darkest areas occurred around the perimeter of the island—the lowest elevations, where melting is most significant—but virtually the entire ice sheet showed below-average reflectivity.

The inset is a close-up view of the area outlined in black on the map. The image is like a digital photo, showing the surface of the ice sheet on July 12, 2012, and it illustrates some of the ways warmer temperatures make the ice sheet less reflective: loss of winter snow cover; exposure of grayish, bare ice; and melt lakes and other liquid water percolating through the ice.

Fresh snow is one of the most reflective surfaces on Earth, sending roughly 84 percent of the sunlight it receives back into space. In contrast, ocean water absorbs almost all of the sunlight it receives. Bare ice sits roughly in between these extremes, reflecting about half of the sunlight that hits it.

In contrast to the brilliant white snow-covered ice at the upper right of the image, the bare ice is dull, in part because it is laced with dust, soot, and other dark particles. Dotting the margin between snow-blanketed and bare ice, blue lakes collect melt water from the ice and snow.

The drop in albedo in 2012 was closely tied to the widespread melt that occurred on the Greenland Ice Sheet, as the areas of unusually low reflectivity coincided with areas of extended melt. The cycle of surface melt and darkening can be self-reinforcing. The more the surface melts, the darker it becomes. The darker it becomes, the more sunlight it absorbs, and the more it melts. The summer of 2012 also brought relatively warm air temperatures and below-average snowfall to the Greenland Ice Sheet, according to the 2012 Arctic Report Card.

Map by NOAA Climate.gov team, based on NASA MODIS albedo data provided by Jason Box, The Ohio State University. Inset image is from NASA’s Terra satellite, courtesy the LANCE MODIS Rapid Response Project. Reviewed by Jason Box.

Summer 2012 brought record-breaking melt to Greenland

Rebecca.Lindsey — Wed, 05 Dec 2012 19:08:27 +0000

A massive ice sheet almost completely covers Greenland, and as summertime temperatures climb and sunlight hours lengthen, parts of the ice sheet surface usually melt, especially at lower elevations near the coast. The summer of 2012, however, brought far more extensive melt than anything observed in the satellite record. In July 2012, surface melt extended over nearly the entire ice sheet—not just around the edges, but also on the high-elevation center.

Maps by NOAA climate.gov team, based on data provided by Thomas Mote, University of Georgia.

These images compare surface-melt conditions on the Greenland Ice Sheet on July 1, 2012 (left), and July 11, 2012 (right). The images were made from observations by the Special Sensor Microwave/Imagers from the Defense Meteorological Satellite Program (DMSP) satellites. Ice undergoing surface melt appears blue, and ice that is not melting appears white.

Some patches of ice escape melt on July 11, but this is a snapshot of a single day. Most areas that avoided surface melt on July 11 experienced melt around that date. An estimated 97 percent of the ice sheet surface melted on July 11 and 12, 2012, and virtually the entire ice sheet surface melted at some point in July 2012. For comparison, from 1981 to 2010, the surface melt extent on a typical July day was roughly 25%.

There is an even more telling indicator of the state of the Greenland Ice Sheet than the total area melting on a single day, and that indicator is the melt index. The melt index is calculated by multiplying the number of days that melt occurred by the area where melt was detected. Scientists use a standardized melt index (shown in the graph below) to put a given year’s melt index value into a historical context; that approach compares that year’s melt index value to the long-term average and the amount of year to year variability in the whole time series. The 2012 melt index was +2.4, compared to the 1979-2012 average. This was nearly twice the previous melt index record, set in 2010, of +1.3.

Graph of Greenland melt index adapted from Figure 5.9 in the 2012 Arctic Report Card.

Not only did Greenland Ice Sheet surface melt in 2012 occur over a bigger-than-average area, it also began about two weeks earlier at lower elevations and, for any given elevation, lasted longer. Some researchers blamed ice sheet surface melt for unusually severe flooding at Kangerlussuaq, an air-transportation hub in southwestern Greenland.

More information about the state of the Greenland Ice Sheet can be found in Chapter 5 of the 2012 Arctic Report Card.

Reviewed by Thomas Mote, University of Georgia.

Thriving on a Sinking Landscape

richard.a.rivera — Thu, 29 Nov 2012 17:48:25 +0000

Police travel down Louisiana Highway 1 on the way to Port Fourchon during Hurricane Isaac on August 30, 2012. Photo courtesy of Tim Osborn.

If you locate South Lafourche Parish, Louisiana, on a map or a satellite image, you’ll see two distinct ribbons that weave their way toward the Gulf of Mexico. One is the lazy, green bayou: an artifact distributary of the once fractal and wild Mississippi River before it was tamed and diverted into the single artery that now runs through New Orleans.

Running parallel to Bayou Lafourche is a two-lane road, Louisiana Highway 1. The LA-1 runs all the way to where the land ends, and then the road rises on great pillars over open water. At the end of the elevated road, Port Fourchon—one of the country’s major ports serving the deepwater oil and gas industry—sits sentry next to Grand Isle, a tiny resort island where kids play on the beaches, barricading their sandcastles against the crush of the tide.

The LA-1 runs through South Lafourche Parish along Bayou Lafourche, past the levee walls and floodgates at Golden Meadow, and all the way to Port Fourchon at the edge of the coast. NASA Aqua satellite image from April 25, 2010, from the EOSDIS Rapid Response Project.

Seven miles of LA-1, from Leeville to Port Fourchon, are elevated to withstand flooding. The remaining eight miles, from Golden Meadow to Leeville, are level with the Bayou, and remain vulnerable to frequent flooding. Image by NOAA climate.gov team based on NASA Landsat data from November 11, 2011, courtesy the USGS GLOVIS website.

As director of the South Lafourche levee district, Windell Curole’s job is not unlike the children playing in the sand; he is constantly bracing against the inevitable. The next big storm is always on the horizon; it’s not a matter of if, as they say, but when. In the grown-up world, plastic shovels and pails are swapped for giant cranes and bulldozers to build levees—giant flood defense walls formed from dirt and concrete.

Beyond the levee walls, Port Fourchon is also fortifying its structures.
The port’s resiliency was put to the test this past summer when the eye of Hurricane Isaac set its sights upon it. Though the port fared well and suffered minor damage, one major weakness in the infrastructure surrounding the port has the potential to impact every American at the gas pump.

Windell Curole and other local residents provide an up-close look at life in South Lafourche Parish, Louisiana, in this video (8 minutes). Increasingly, life on the Gulf Coast poses challenges for those who live and work there. Video (8 min, 14 sec) by NOAA climate.gov team.

For Curole and others—energy companies, port managers, and key decision-makers in the community—the availability of accurate data is critical. In a vulnerable landscape, it could mean the difference between flooding and thriving on a sinking landscape. A drive down LA-1, he tells me, will show me all I need to know about why the land is worth fighting for.

The costs of drought on the Rio Grande

Rebecca.Lindsey — Tue, 13 Nov 2012 17:09:48 +0000

By the end of September, nearly all the surface water in the Lower Rio Grande (map) had been drained. Below New Mexico’s Elephant Butte Reservoir, the river was flowing at a trickle, and sandy bars were exposed where the chocolate-colored river had been flowing as recently as mid-September. At Greg Daviet’s pecan farm in the Mesilla Valley outside Las Cruces, the drone of groundwater pumps filled the air, and wells spit crystalline water onto thirsty orchards.

This article is the second in a two-part series exploring effects of the current drought in New Mexico’s Lower Rio Grande Valley and highlights the impacts to pecan farming. Part one discussed observed and expected changes in water supply and how regional water managers are responding.

Despite another dry year—the ninth time in the last decade that farmers received a fraction of the surface water they need to sustain their crops—the pecan trees are healthy thanks to bountiful groundwater that is pumped up from wells to nourish the crop.

Pecan trees near Hatch, New Mexico, bathed in irrigation water from wells. Photo by Zack Guido.

The extra pumping during the dry times, however, comes at a price. Groundwater costs more per acre-foot than surface water and is more harmful to crops in the long run, because the water is saltier. For Daviet and some other farmers in the region, the drought’s toll is burdensome—but not bankrupting—and may force some creative measures to lessen the financial strain.

“The water is still sufficient in a drought, but how we [manage] it needs to change,” Daviet said. “Drought will never be as profitable as wet times.”

For other farms, however, the added expenses from continued dry conditions may push the owners to the brink.

Current Conditions
Back-to-back La Niña events during the 2010 and 2011 winters helped steer storms away from the Upper Rio Grande Basin in Colorado, where most of the water flowing in the Rio Grande originates. Rain and snow totaled less than 82 percent of the 1971–2000 average during those winters.

Snowmelt from the Rocky Mountains in southern Colorado is the most important source of water for the Rio Grande. The past two winters (October-April), the river’s mountainous headwaters have received much less precipitation than normal (1971-2000 average). Maps by Larry Belcher, based on PRISM data from Oregon State University.
large 2010-2011 map | large 2011-2012 map

The scant precipitation has contributed to a decreasing trend in reservoir storage that began around 1999, and as of September 1, the region’s largest reservoir—Elephant Butte—stood at less than 5 percent of capacity. The water available for future irrigation, doled out by the Elephant Butte Irrigation District is now completely exhausted.

For the foreseeable future, the amount of surface water available to farmers will depend entirely on the previous winter’s precipitation and likely will be insufficient to meet demand. To compensate, irrigators will continue to rely heavily on groundwater.

“Around half a million acre-feet of water is the amount of water that needs to be put on the fields [in Elephant Butte Irrigation District],” Daviet said. “In wet years, the reservoirs provide plenty of that. In years where we are drier, we supplement that with groundwater pumping.”

A Protective Shield
While Elephant Butte Reservoir stores water above ground, porous sediments below the river form another, larger reservoir. The aquifer beneath Mesilla Valley is more than 2,000 feet thick in some places, according to recent hydro-geological studies in the area, providing ample water that safeguards farmers during droughts.

“It’s a rather unique system we have here,” said Phil King, professor of civil engineering at New Mexico State University and a consultant for the Elephant Butte Irrigation District. “The surface water and the groundwater are all the same water; they are closely linked. When there’s plenty of surface water, the aquifer recharges. In times of drought, though, you have to go back and make withdrawals that deplete the groundwater that will be paid back by future surface water supplies. This allows the region to buffer wild fluctuations.”

Groundwater not only protects trees from inadequate surface water allotments, it also allows farmers to apply water on demand. Groundwater is critical for ensuring productive crops and is needed even in times of abundant surface water because bottlenecks can arise in the water district’s deliveries. In the middle of the summer when demand is high, for example, the district can move only a fraction of the water needed, and some farmers have to wait. In the absence of groundwater, these delays can stress the trees and ultimately reduce crop yields.

Even though groundwater pumping has ramped up in recent years, water levels have dropped only 30 feet at Daviet’s farm after 10 years of drought. With hundreds of feet more of water-bearing sediments and wells that penetrate more than 300 feet deep, his concern about running out of water is low.

“Do I think that we will ever see a drought that will deplete 300 feet?” Daviet said. “Probably not in my lifetime.”

Daviet happens to live in one of the sweet spots for water in the Lower Rio Grande. About 40 miles north, near Hatch, the aquifer is substantially smaller and water is found at depths less than 200 feet, according to Rosie Lack, sales executive for Lack Farms which grows onions, chili, cotton, and other crops on about 1,500 acres.

The Rio Grande (image center) provides irrigation water in southern New Mexico’s otherwise arid landscape, creating a patchwork of green fields along the chocolate-colored river. When surface water dries up, growers near Hatch (top), where the aquifer is shallower, have a harder time tapping groundwater than growers near Las Cruces, where the aquifer is deeper. Photo courtesy the NASA JSC Gateway to Astronaut Photography of the Earth.

Most of the wells on Lack Farms are 60 feet deep, and recent declines in the water table have caused groundwater levels to dip below the intake valves when the pumps are ramped up. This causes water and air to be drawn together, straining the pumps and reducing water flow.

“Our wells are surging; our water level is dropping,” Lack said, noting that continued low surface water allotments will be difficult to overcome. “I don’t think we could last more than five years [if low surface water allocations continue].”

The Added Costs
Even where ample water exists, farmers like Daviet are not immune to drought. And, almost everywhere in the Lower Rio Grande Valley, the drought has dried up savings accounts. “When we have to pump nearly all of our water, for a pecan farmer it adds 10 to 15 percent to our normal expenditures,” Daviet said.

These unwanted costs can skyrocket when large capital improvements need to be made to irrigation systems—added investments that occur more often in times of drought. When watering, Daviet needs to flood his fields with about 2,500 gallons per minute to quench the thirst of his trees. This year, he could pump only 1,900 gallons after one well failed, and the lower water tables diminished his capacity in his other two wells.

“About every 10 feet that our water table drops, I lose about a 100 gallons per minute,” Daviet said.

To overcome this shortfall, Daviet was forced to spend $150,000 on a new well, a significant portion of his operating budget. For profitable farms, these added expenditures can be absorbed. For farms functioning on the margins of profitability, it can push them over the edge.

“Big infrastructure improvements could be as much as 30 to 40 percent [of annual budgets] in years that big improvements need to be done to enable groundwater pumping,” Daviet said. “When you are talking about that level of investment, if you have a farm that is marginal, that could be the straw that breaks them.”

The added costs affect more than pecan growers. In Hatch, the chili pepper is king. Jim Lytle’s family have been farming the valley since the late 1800s and have helped pioneer chili production in the region. A variety of pepper, the one found on most chili relleno dishes, even bears the name of Lytle’s father—The Big Jim. The drought has been a burden on his family as well.

Young chili peppers sprout in Jim Lytle’s field near Hatch, New Mexico, in early July 2012. Photo by Zack Guido.

“We use approximately four feet of water to irrigate one acre of chili,” Lytle said. “We were only allocated [10] inches [this year], so the rest of it we have to pump. That’s going to impact us significantly, and what it comes to is at the tail end, we are going to make, probably, half of what we normally make.”

The recent dry conditions have lowered crop yields at Lack Farms while also raising production costs. “I feel like the drought has probably affected the yield potential by at least 40 percent and our expenses are up too,” Lack said.

Salty Soils
Groundwater also has other, hidden costs. Because the local geologic deposits are rich in salts and other minerals and groundwater spends long times in contact with them, elements are extricated from the sediments much like hot water extracts caffeine from coffee or tea. Consequently, groundwater carries higher concentrations of salts and minerals than surface water.

“Those minerals and salts can be detrimental to the health of the trees,” Daviet said.

The drought exacerbates salinity problems because increased pumping lowers water tables, causing pumps to draw more water from upper portions of the aquifer where salinity is highest. It also pulls water from the fringes of the aquifer, where salts concentrate. In other words, the longer and more vigorously wells are pumped, the saltier the water becomes, eventually leading to saltier soils. This is particularly true near Hatch, where the aquifer is shallower.

“This is our fourth year of limited river water and so we’re just fighting sodium in the soils,” Lack said. “You can walk across the ground and it’s like stepping on crackers.”

In the Lower Rio Grande Valley, fighting salinity is best waged with surface water, a difficult proposition when the resource is scarce. It’s not impossible, however. It requires new coping strategies, including more coordinated management.

Daviet, for example, can sell his surface water allocation to farms in Hatch in return for adequate financial compensation for the added expenditure of pumping more groundwater. Leasing water within an established water market in this way can also help protect against future limited surface water supplies by directing limited surface supplies to areas with less accessible groundwater supplies.

“We can work together to find solutions to these complex problems,” Daviet said. “Drought is not the end of the world. We can adjust to it. We do adjust to it, as long as you don’t fight change and [instead] try to adapt to it.”

Reviewed by Greg Daviet and Julie Brugger, University of Arizona/Climate Assessment for the Southwest.

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