August 29, 2017
Flood estimates from GFMS using IMERG input show evolution of flooding over the last few days, with expansion from Houston area to southeastern Texas and Louisiana. Satellite-based rainfall (GPM IMERG) from now Tropical Storm Harvey over the last three days compares fairly well with raingauges, except for peak values. IMERG has peaks of about 500 mm (~ 20”) around Houston, whereas gauges indicate over 35”. Contour at 150 mm, however, agrees reasonably well.
August 28, 2017
Despite its earlier demise, after rejuvinating over the warm waters of the Gulf of Mexico, Hurricane Harvey has become a major weather maker as it unleashes historical flooding over parts of coastal Texas. Harvey began on the 17th of August as a weak tropical storm about 250 miles (~400 km) east of Barbados in the Leeward Islands. Over the next two days, Harvey continued moving steadily westward passing through the Leeward Islands as a still weak tropical storm and entered into the east central Caribbean. On the 19th, Harvey succumbed to the effects of northeasterly wind shear over the central Caribbean and lost its cyclonic circulation and weakened back into a tropical wave. The remnants of what was once Harvey then passed over the Yucutan Peninsula and into the Bay of Campeche. Typically, it is hard for a system to reform after dissipating as well as after passing over land. However, the environmental conditions were favorable for development and the water temperatures in the Gulf of Mexico very warm. This allowed Harvey first to reform into a tropical depression on the morning of the 23rd of August then strengthen back to a tropical storm later that evening. Having recovered its structure, Harvey was then able take further advantage of the low wind shear and warm waters and continue to intensify, becoming a hurricane by midday on the 24th and then rapidly intensifying overnight into a Category 2 storm with maximum sustained winds reported at 110 mph (~175 kph) by the National Hurricane Center (NHC) at 15:00 UTC (10:00 am CDT) the next morning. Now moving northwest across the western Gulf and Mexico and headed straight for the central Texas coast, Harvey continued to get stronger during the day on the 25th and reached its peak intensity as a Category 4 storm with sustained winds of 130 mph (215 kph) at 6:00 pm CDT according to NHC. Harvey maintained this intensity until it made landfall later that evening at around 10:00 pm CDT as a Category 4 hurricane near Rockport, Texas, about 30 miles east-northeast of Corpus Christi. After making landfall, Harvey weakened and its winds decreased back down to tropical storm intensity by 1:00 pm CDT the next day on the 26th; however, as had been forecast, the steering currents collapsed, bringing the storm to a near stand still just inland from the Texas Gulf Coast and setting the stage for a catostrophic flooding event.
August 27, 2017
The above image is a screenshot of the flood extent map created by the ARIA team at NASA-JPL/Caltech, derived from the ALOS-2 ScanSAR data acquired on 8/27/17 (~1:30PM Central Time) over Texas including Houston. This Flood Proxy Map (FPM) covers an area of 350-by-350 km and is derived from Japan Aerospace Exploration Agency's (JAXA's) ALOS-2 PALSAR-2 pre- (2017-07-30) and post-event (2017-08-27) Synthetic Aperture Radar (SAR) amplitude images. The pixels in light blue indicate areas likely flooded. Individual pixel size is about 50-by-50 m. Anecdotal preliminary validation was implemented with some number of local ground observations. This FPM should be used as guidance to identify areas that are likely flooded, and may be less reliable over urban areas. The FPM was created by Advanced Rapid Imaging and Analysis (ARIA) team at NASA-JPL/Catech, and the ALOS-2 data were accessed through the International Charter.
August 25, 2017
NASA’s Short-term Prediction Research and Transition (SPoRT) Center collaborated with the Naval Research Laboratory to integrate false color composites of passive microwave brightness temperatures that are helpful for identifying the center of circulation of storms like Hurricane Harvey, especially when thick cloud cover may otherwise obscure the center of the circulation. A false color composite is generated using 89 GHz brightness temperatures from the Global Precipitation Measurement (GPM) Microwave Imager (GMI), identifying the strongest thunderstorms associated with Harvey in bright reds, along with the outermost intense rainbands that were striking the coast of Texas on Friday, August 25 (bottom image). The eye of the storm can be seen in the center, along with the counterclockwise circulation of the surrounding rainbands. These images are shared with the National Weather Service and the National Hurricane Center to help integrate the use of unique NASA mission imagery and products within the weather forecasting process.The above image shows rainfall rates for the same overpass at 11:46 UTC which utilizes the GMI and Dual-frequency Precipitation Radar (DPR). These data are routinely used by NRL and other forecast groups to improve tropical cyclone tracking and forecasts.
August 25, 2017
Hurricane Harvey's has continued to intensify today as it moves toward the Texas coast. Bands of rain from the hurricane were affecting the Gulf coast from Louisiana to southeastern Texas. The Global Precipitation Measurement (GPM) mission core observatory satellite had another look at hurricane Harvey on August 25, at 7:50 AM CDT (1150 UTC) as it was menacing the Texas gulf coast. GPM's Dual-Frequency Precipitation Radar (DPR) instrument scanned precipitation within powerful storms wrapping around the eastern side of the hurricane. DPR found that intense storms in that area were dropping rain at a rate greater than 3.2 inches (82 mm) per hour. GPM's Radar (DPR Ku Band) also was used to examine the 3-D configuration of precipitation within the storms on hurricane Harveys' eastern side. DPR showed that storm tops there reached altitudes above 9.2 miles (14.8 km). GPM's radar found the tallest of these powerful storms in a band of precipitation that was approaching the coastline near the Texas and Louisiana borders. These storms were measured by GPM's radar reaching an altitude of over 10.3 miles (16.6 km). Harvey is expected to be a Category 3 hurricane when it hits the Texas coast near Corpus Christi early Saturday morning. Storm surge flooding along the Texas coast is expected to reach heights of 6 to 12 feet (1.8 - 3.7 meters). Catastrophic flooding is predicted in the area due to an expected 15 to 25 inches (381.0 to 635 mm) of rainfall.
August 9, 2017
Click here to view the full image collection and download high quality georeferenced images. This collection of digital camera images was taken by astronauts onboard the International Space Station on August 9st, 2017, then manually georeferenced by members of the Earth Science and Remote Sensing Unit at NASA Johnson Space Center
August 8, 2017
Agricultural crops can wither in a flash when the days turn hot, the air dries, the rain stops and moisture evaporates quickly from the soil. A new early warning system developed by two nationally recognized centers at the University of Nebraska-Lincoln, along with the U.S. Geological Survey, can help alert stakeholders as drought begins. The Quick Drought Response Index, or QuickDRI, is a weekly alarm sensitive to early-stage drought conditions and rapidly evolving drought events. Developed by the National Drought Mitigation Center in coordination with USGS, the index combines and analyzes four drought indicators – precipitation, soil moisture, vegetation health and evaporative moisture loss from plants — all at once to better "see" drought conditions emerge before traditional drought-monitoring tools. QuickDRI transitioned to operational status with the U.S. Drought Monitor and USGS in June, 2017, improving our ability to detect and monitor drought across the U.S.
August 8, 2017
This article is one of many that highlighted the work of the Cyanobacteria Assessment Network (CyAN), a multi-agency project among the National Aeronautics and Space Administration (NASA), National Oceanic and Atmospheric Administration (NOAA), U.S. Geological Survey (USGS), and EPA to develop an early warning indicator system using historical and current satellite data to detect algal blooms in U.S. freshwater systems. This research supports federal, state, and local partners in their monitoring efforts to assess water quality to protect aquatic and human health. EPA Region 8 requested specific support for the State of Utah with early access to the imagery based on the severity of blooms from the previous year. A cyanobacteria bloom in Utah Lake was identified just before the July 4th weekend. The news articles related to the Utah DEQ press release acknowledge the bloom was first detected via satellite imagery early warning!
August 8, 2017
In June of 2017, Earth & Space Science News released an article on the use of Earth Observations to better inform farmers of irrigation needs. Researchers from the University of Washington and Pakistan are using 21st century technology to revive farming as a profitable profession in the Indus Valley.
August 8, 2017
On June 11, 2017, the Los Angeles Times ran a front-page story on NASA's SnowEx campaign titled "Measuring the snowpack goes high-tech with airborne lasers and radar".