Archive for the Press: Climate Science category



Today, scientists estimate that between one-third and one-half of our planet’s land surfaces have been transformed by human development.

A MODIS image revealing the widespread deforestation, light green and brownish areas, taking place near Mato Grosso, Brazil.

Image: Deforestation by Satellite: This image, taken April 21, 2002 by the Moderate-resolution Imaging Spectroradiometer (MODIS) flying aboard NASA’s Terra satellite reveals the widespread deforestation (light green and brownish areas) taking place near Mato Grosso, Brazil. Red dots show the locations of actively burning fires. Credit: NASA/MODIS Land Rapid Response Team

Now, a new study is offering insight into the long-term impacts of these changes, particularly the effects of large-scale deforestation in tropical regions on the global climate. Researchers from Duke University, Durham, N.C., analyzed multiple years of data using the NASA Goddard Institute for Space Studies General Circulation Computer Model (GCM) and Global Precipitation Climatology Project (GPCP) to produce several climate simulations. Their research found that deforestation in different areas of the globe affects rainfall patterns over a considerable region.

Deforestation in the Amazon region of South America (Amazonia) influences rainfall from Mexico to Texas and in the Gulf of Mexico. Similarly, deforesting lands in Central Africa affects precipitation in the upper and lower U.S Midwest, while deforestation in Southeast Asia was found to alter rainfall in China and the Balkan Peninsula. It is important to note that such changes primarily occur in certain seasons and that the combination of deforestation in these areas enhances rain in one region while reducing it in another.

This finding contradicts earlier research suggesting deforestation would result in a reduction in precipitation and increase in temperature in the Amazon basin, but carry no detectable impact on the global water cycle.

“Our study carried somewhat surprising results, showing that although the major impact of deforestation on precipitation is found in and near the deforested regions, it also has a strong influence on rainfall in the mid and even high latitudes,” said Roni Avissar, lead author of the study, published in the April 2005 issue of the Journal of Hydrometeorology.

Specifically, deforestation of Amazonia was found to severely reduce rainfall in the Gulf of Mexico, Texas, and northern Mexico during the spring and summer seasons when water is crucial for agricultural productivity. Deforestation of Central Africa has a similar effect, causing a significant precipitation decrease in the lower U.S Midwest during the spring and summer and in the upper U.S. Midwest in winter and spring. Deforestation in Southeast Asia alters rainfall in China and the Balkan Peninsula most significantly.

Elimination of any of these tropical forests, Amazonia, Central Africa or Southeast Asia, considerably enhances rainfall in the southern tip of the Arabian Peninsula. However, the combined effect of deforestation in all three regions shifts the greatest precipitation decline in the U.S. to California during the winter season and further increases rainfall in the southern tip of the Arabian Peninsula.

Improved understanding of tropical forested regions is valuable to scientists because of their strong influence on the global climate. The Amazon Basin literally drives weather systems around the world. The tropics receive two-thirds of the world’s rainfall, and when it rains, water changes from liquid to vapor and back again, storing and releasing heat energy in the process. With so much rainfall, an incredible amount of heat is released into the atmosphere – making the tropics the Earth’s primary source of heat redistribution.

“Deforestation does not appear to modify the global average of precipitation, but it changes precipitation patterns and distributions by affecting the amount of both sensible heat and that released into the atmosphere when water vapor condenses, called latent heat,” said Avissar. “Associated changes in air pressure distribution shift the typical global circulation patterns, sending storm systems off their typical paths.” And, because of the Amazon’s location, any sort of weather hiccup from the area could signal serious changes for the rest of the world like droughts and severe storms.

Clearly, land-cover changes in tropical regions carry potentially significant consequences on water resources, wildfire frequency, agriculture and related activities at various remote locations. And while greenhouse gas emissions and pollutants receive considerable attention, this study shows that land-cover change is another important parameter that needs to be considered in climate policies, especially since deforestation rates in tropical Africa, Southeast Asia, and South America have remained constant or have increased over the past two decades. Land-cover change, depending on its nature, can either mitigate or exacerbate greenhouse warming.

The researchers caution that their results are based on numerical simulations performed with a single general circulation model and that reproducing the experiment with other computer models using different atmospheric variables would be beneficial. Current research is attempting to answer why deforestation has such a major influence on precipitation patterns during respective seasons.

Original press release: Tropical Deforestation Affects Rainfall in the U.S. and Around the Globe (NASA)

Friday (16 September) is International Day for the Preservation of the Ozone Layer. This year scientists at British Antarctic Survey (BAS) commemorate their discovery of the Antarctic ‘ozone hole’ 20 years ago and commend the historic international agreement (the Montreal Protocol 1987) that will lead to its eventual recovery.

Jonathan Shanklin, one of the researchers who made the discovery says,

“The 2005 hole is larger and deeper than the holes that formed when the discovery was made but the situation would be much worse if the Montreal Protocol had not come into force. This agreement shows us that global action by governments to stop the release of ozone depleting chemicals really can help society to successfully mitigate a global environmental problem. We are still experiencing large losses of Antarctic ozone each spring because CFCs and other chemicals live for a long time in our atmosphere. However, the ban ensures that we will see an improvement in the future. We now need to take similar actions to control greenhouse gasses, otherwise we will bequeath future generations a significantly different climate from that of today.”

Covering an area of around 22 million square kilometres this year’s hole is a little smaller than the record-breaking event in August 2003. Measurements made during August and September at BAS Halley and Rothera Research Stations reveal a 50% reduction on normal ozone levels over the base of the Antarctic Peninsula and the Weddell Sea, and a 20% reduction over the tip of South America and the Falkland Islands. The increased ultra violet light reaching the surface poses a medical hazard to people living under the ‘hole’ and without suitable protection people face the prospect of rapid sunburn and potentially more serious skin damage.

Original press release: 20th Anniversary of ozone hole discovery – International Ozone Day (BAS)

Two NASA satellites, planned for launch no earlier than Oct. 26, will give us a unique view of Earth’s atmosphere. CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) are undergoing final preparations for launch from Vandenberg Air Force Base, Calif.

CloudSat and CALIPSO will provide a new, 3-D perspective on Earth’s clouds and airborne particles called aerosols. The satellites will answer questions about how clouds and aerosols form, evolve and affect water supply, climate, weather and air quality.

CloudSat and CALIPSO employ revolutionary tools that will probe Earth’s atmosphere. Each spacecraft carries an “active” instrument that transmits pulses of energy and measures the portion of the pulses scattered back to the instrument.

CloudSat’s cloud-profiling radar is more than 1,000 times more sensitive than typical weather radar. It can detect clouds and distinguish between cloud particles and precipitation. “The new information from CloudSat will answer basic questions about how rain and snow are produced by clouds, how rain and snow are distributed worldwide and how clouds affect the Earth’s climate,” said Dr. Graeme Stephens, CloudSat principal investigator at Colorado State University, Fort Collins, Colo.

CALIPSO’s polarization lidar instrument can detect aerosol particles and can distinguish between aerosol and cloud particles. “With the high resolution observation that CALIPSO will provide, we will get a better understanding of aerosol transport and how our climate system works,” said Dr. David Winker, CALIPSO principal investigator at NASA’s Langley Research Center, Hampton, Va.

The satellites will be launched into a 438-mile circular, sun-synchronous polar orbit, where they will fly in formation just 15 seconds apart as members of NASA’s “A-Train” constellation with three other Earth Observing System satellites. The A-Train includes NASA’s Aqua and Aura satellites and France’s PARASOL satellite.

The usefulness of data from CloudSat, CALIPSO and the other A-Train satellites will be much greater when combined. The combined set of measurements will provide new insight into the global distribution and evolution of clouds that will lead to improvements in weather forecasting and climate prediction.

CloudSat is managed by NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif. The radar instrument was developed at JPL, with hardware contributions from the Canadian Space Agency. Colorado State University provides scientific leadership and science data processing and distribution.

Other contributions include resources from the U.S. Air Force and the U.S. Department of Energy. Ball Aerospace and Technologies Corp. designed and built the spacecraft. A host of U.S. and international universities and research centers provides support to the science team. Some of these activities are contributed as partnerships with the project.

CALIPSO was developed through collaboration between NASA and the French Space Agency, Centre National d’Etudes Spatiales (CNES). NASA’s Langley Research Center leads the CALIPSO mission and provides science team leadership, systems engineering, payload mission operations, and validation, processing and archiving of data. Langley also developed the lidar instrument in collaboration with the Ball Aerospace and Technologies Corp., which developed the onboard visible camera.

NASA’s Goddard Space Flight Center, Greenbelt, Md., provides project management, system engineering support and overall program management. CNES provides a PROTEUS spacecraft developed by Alcatel, the imaging infrared radiometer, payload-to-spacecraft integration and spacecraft mission operations. The Institut Pierre Simon Laplace in Paris provides the imaging infrared radiometer science oversight, data validation and archival. Hampton University provides scientific contributions and manages the outreach program.

Original press release: NASA Satellites Will Reveal Secrets of Clouds and Aerosols (NASA)

Scientists using satellite imagery found that at least 23 percent of the water released from the mouth of the Mississippi River from July through September 2004 traveled quite a distance – into the Gulf of Mexico, around the Florida Keys, and into the Atlantic Ocean.

This image taken August 14, 2002, by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA’s Terra satellite, shows black water off Sanibel Island, Florida, the hook-shaped island on the western coast at the midway point of the image.

The researchers combined data from the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra and Aqua satellites with information collected from ships to study the water discharge, appearing as a dark plume that stretched from the Mississippi Delta, around Florida and up to the Georgia coast. MODIS detects the color of the ocean due to changes in the amount of tiny ocean plants floating on the ocean’s surface known as phytoplankton, or algae and other decaying materials.

“This is the first time we have been able to estimate the amount or volume of freshwater discharged and carried over such remote distances. By combining the very detailed data from MODIS with observations from ships, we got a three-dimensional view of the Mississippi plume,” said Chuanmin Hu, of the College of Marine Science, University of South Florida, St. Petersburg, Fla., and lead author of the study. By using MODIS data with information on sea surface currents and sea salt levels (salinity), the scientists estimated that about 20 billion tons of Mississippi River discharge reached the Florida Straits and Gulf Stream off the Georgia coast. This is equivalent to about four times the volume of Lake Okeechobee, the largest lake in Florida.

In early July 2004, the dark water plume traveled south along the eastern edge of the Loop Current off southwest Florida, reaching the Florida Keys by late July 2004. By early August, MODIS images showed that the plume had expanded along the Gulf Steam as far away as the Georgia coast. The plume was typically 30 to 65 feet deep with a width of 6 to 12 miles; although occasionally was as wide as 30-37 miles, before dissipating in October 2004.

While many factors, like ocean eddies – that mix waters of varying characteristics – influence the evolution of such events, climate and weather patterns also play a role. For instance, following the Great Midwest Flood of 1993, Mississippi River water also moved into the Florida Current. In 2004, heavy summertime rainfall may have contributed to the plume’s large size and persistence. But “it’s still too early to know if there is a concrete connection between climate and the occurrence of these events, as much further study is needed,” said Hu.

Complete article (including some more cool images): Satellites Spot Mighty Mississippi – In The Atlantic (NASA)

The Amazon, a vast tropical forest stretching across South America, is so large that is virtually impossible to study the evolving landscapes within the basin without the use of satellites. Scientists have used satellite imagery of the Amazon for more than 30 years to seek answers about this diverse ecosystem and the patterns and processes of land cover change. This technology continues to advance and a new study shows that NASA satellite images can allow scientists to more quickly and accurately assess deforestation in the Amazon.

Image: Location of Landsat test scenes and field validation area within the Brazilian Amazon. Percent tree cover values from the 2001 Vegetation Continuous Fields (VCF) product show the extent of forest cover in the region. Map subsets show 2002 Instituto Nacional de Pesquisas Espaciais (INPE) Prorgram for the Estimation of Deforestation in the Brazilian Amazon (PRODES) classifications for each test scene over 2001 VCF percent tree cover. Test scenes are presented in counter-clockwise order, beginning in the northeast with scene 223/66 and followed by 227/65 in the north, 232/67 in the west, and the cluster of scenes 226/67, 226/68, and 225/69 in central Mato Grosso state. Credit: Doug Morton, University of Maryland-College Park

Researchers from the University of Maryland-College Park, Brazil’s National Institute for Space Research (INPE) of Sao Jose dos Campos, Brazil, and South Dakota State University, Brookings, S.D., compared multiple years of data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra and Aqua satellites to data collected from the high-resolution Landsat satellite. They found that MODIS images can rapidly and reliably detect changes in Amazon land cover.

Unlike MODIS data, analyses of high spatial resolution data demand extensive storage and processing requirements. And, in tropical forest regions, image quality is often reduced by cloud cover and infrequent coverage of high-resolution images. But MODIS obtains images of the Amazon up to four times per day and evaluations of the quality of data are provided with the image, clearly marking areas of clouds, water, or high aerosols. These impacts are further minimized with daily composites created through the combination of individual images.

While high resolution imagery is still needed when estimating the total area of deforestation or when identifying small clearings, “the most exciting finding of this study is that it shows MODIS can permit regional analyses of land cover in a matter of days, a substantial reduction in effort in comparison to the months now required with Landsat,” said Douglas Morton, scientist at the University of Maryland-College Park and lead author of the new study.

Deforestation rates in tropical Africa, Southeast Asia, and South America have remained constant or have increased over the past two decades, altering global carbon emissions and climate while elevating the need for frequent and accurate assessment of forest loss. In the Brazilian Amazon alone, where the growth of cattle ranching and cropland agriculture are the primary causes of forest clearing, about 7,700 square miles of forest are clear-cut and burned each year, or roughly the area of New Jersey.

This study found a marked trend of larger and more extensive deforestation events between 2001 and 2004 in Mato Grosso State, Brazil, which was later confirmed on the ground. Information like this is so valuable to scientists because the Amazon literally drives weather systems around the world.

The tropics receive two-thirds of the world’s rainfall, and when it rains, water changes from liquid to vapor and back again, storing and releasing heat energy in the process. With so much rainfall, an incredible amount of heat is released into the atmosphere – making the tropics the Earth’s primary source of heat redistribution. And, because of the Amazon’s location, any sort of weather hiccup from the area could signal serious changes for the rest of the world like droughts and severe storms.

Global climate is also affected when Amazon burning practices to clear fields for farming result in large fires that create air pollution and release tiny particles, known as aerosols. Aerosols can both heat and cool the air, depending on size, shape and color. High concentrations of biomass burning aerosols also directly impact the local climate by increasing cloud formation but decreasing rainfall. In very smoky regions, cloud droplets form around the aerosol particles, but may never grow large enough to fall as rain.

Building on the results of this study, Brazil’s INPE has developed a near or almost real time monitoring application for deforestation detection known as the Real Time Deforestation Monitoring System (DETER) system.

While this study highlights the challenges of monitoring deforestation and the use of MODIS data in the Amazon, it also shows that similar MODIS analyses could form the basis for a wide array of regional studies in a highly-automated fashion, with both scientific and decision-making utility.

The complete article (with some very cool images): NASA Satellite Data Used by INPE Provides Rapid Analysis of Amazon (NASA)

After leaving the Space Test Centre in Germany on 29 August, CryoSat has safely arrived at the Plesetsk Cosmodrome, about 800 km north of Moscow, Russia. CryoSat is scheduled for launch on 8 October 2005 at 15h02 UTC.

The convoy was initially transported by truck from IABG (Industrieanlagen-Betriebsgesellschaft mbH) in Ottobrunn to Munich airport, where it was stored in a hangar over night before being loaded onto an Antonov-124 cargo aircraft for the three and a half hour flight to Talagi Airport, Archangel in Russia.

The spacecraft, however, did not travel alone – it was accompanied by a whole host of vital support equipment resulting in the shipment weighing in at around 60 tonnes and valuing some 80 million euros. The CryoSat satellite was packed in its own nitrogen-pressurized container, while nine other containers housed items such as racks of electrical equipment to operate and test the spacecraft, and heavy mechanical equipment to lift and turn the satellite allowing engineers to gain overall access to the structure in the Integration Facility at the launch site.

An advance team was already in Archangel, and after they had ensured that everything was in order to receive the cargo on arrival, they gave the go-ahead for the flight from Munich to take-off. After a safe landing in Archangel in the evening of 30 August, the convoy was transported by truck to the local train station where it was lifted onto railcars. For reasons of safety and security the special train made its journey through the night, arriving in Plesetsk on 1 September. So that the cargo wasn’t at risk of being damaged the train had to travel extremely slowly. It therefore took most of the night to cover the 200 km journey southward to CryoSat’s final destination.

CryoSat’s safe arrival in Plesetsk marks an important milestone in the project. The shipment was carried out with relative ease. Guy Ratier, CryoSat Project Manager commented, “Everything went according to plan. It is not the first time that ESA has used an Antonov, a fantastic plane indeed, to transport satellites to their launch site. Loading the plane was just a routine operation. The train transport between Archangel and Plesetsk was also uneventful, thanks to the wide experience gained by Eurockot and Khrunichev during previous campaigns. For sure, I consider this transportation step as a very good start towards a successful launch campaign.”

CryoSat is the first in the series of Earth Explorer missions to be launched. Earth Explorers are small, inexpensive missions designed to provide some fast answers to a specific aspect of the Earth’s environment. In this case, CryoSat is to determine rates of change in the thickness of marine and continental ice cover.

With speed and a limited budget in mind, the CryoSat project have found an elegant solution for launch, that being a Russian Rockot vehicle, which is actually a converted SS-19 ballistic missile launcher with an additional Breeze-KM upper stage. CryoSat will be the first ESA mission launched on Rockot followed by the Earth Explorers GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) in 2006 and SMOS (Soil Moisture and Ocean Salinity) in 2007.

Now that CryoSat has arrived, unloading and unpacking is underway and the launch campaign will begin. Members of the CryoSat team in Plesetsk will oversee the thorough final testing period before the satellite is eventually jointed to the fairing and prepared for launch on 8 October.

Original press release: CryoSat Arrives Safely at Launch Site in Russia (ESA)

Image source: ESA

After leaving the Space Test Centre in Germany on 29 August, CryoSat has safely arrived at the Plesetsk Cosmodrome, about 800 km north of Moscow, Russia. CryoSat is scheduled for launch on 8 October 2005 at 15h02 UTC.

The convoy was initially transported by truck from IABG (Industrieanlagen-Betriebsgesellschaft mbH) in Ottobrunn to Munich airport, where it was stored in a hangar over night before being loaded onto an Antonov-124 cargo aircraft for the three and a half hour flight to Talagi Airport, Archangel in Russia.

The spacecraft, however, did not travel alone � it was accompanied by a whole host of vital support equipment resulting in the shipment weighing in at around 60 tonnes and valuing some 80 million euros. The CryoSat satellite was packed in its own nitrogen-pressurized container, while nine other containers housed items such as racks of electrical equipment to operate and test the spacecraft, and heavy mechanical equipment to lift and turn the satellite allowing engineers to gain overall access to the structure in the Integration Facility at the launch site.

An advance team was already in Archangel, and after they had ensured that everything was in order to receive the cargo on arrival, they gave the go-ahead for the flight from Munich to take-off. After a safe landing in Archangel in the evening of 30 August, the convoy was transported by truck to the local train station where it was lifted onto railcars. For reasons of safety and security the special train made its journey through the night, arriving in Plesetsk on 1 September. So that the cargo wasn’t at risk of being damaged the train had to travel extremely slowly. It therefore took most of the night to cover the 200 km journey southward to CryoSat’s final destination.

CryoSat’s safe arrival in Plesetsk marks an important milestone in the project. The shipment was carried out with relative ease. Guy Ratier, CryoSat Project Manager commented, “Everything went according to plan. It is not the first time that ESA has used an Antonov, a fantastic plane indeed, to transport satellites to their launch site. Loading the plane was just a routine operation. The train transport between Archangel and Plesetsk was also uneventful, thanks to the wide experience gained by Eurockot and Khrunichev during previous campaigns. For sure, I consider this transportation step as a very good start towards a successful launch campaign.”

CryoSat is the first in the series of Earth Explorer missions to be launched. Earth Explorers are small, inexpensive missions designed to provide some fast answers to a specific aspect of the Earth’s environment. In this case, CryoSat is to determine rates of change in the thickness of marine and continental ice cover.

With speed and a limited budget in mind, the CryoSat project have found an elegant solution for launch, that being a Russian Rockot vehicle, which is actually a converted SS-19 ballistic missile launcher with an additional Breeze-KM upper stage. CryoSat will be the first ESA mission launched on Rockot followed by the Earth Explorers GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) in 2006 and SMOS (Soil Moisture and Ocean Salinity) in 2007.

Now that CryoSat has arrived, unloading and unpacking is underway and the launch campaign will begin. Members of the CryoSat team in Plesetsk will oversee the thorough final testing period before the satellite is eventually jointed to the fairing and prepared for launch on 8 October.

Original press release: CryoSat Arrives Safely at Launch Site in Russia (ESA)