This past September, even as the United States was still slowly recovering from the floods of devastating Hurricane Isaac, the Korean Peninsula was being hit by Typhoon Sanba, the third typhoon of the year to impact Korea. (MSNBC article: "Typhoon Sanba batters 2 Koreas after drenching Japan”). Sanba caused the evacuation of thousands of people, huge amounts of property damage, and tragic loss of life.
The Atmospheric Infrared Sounder (AIRS), a high spectral resolution infrared spectrometer on NASA's Aqua satellite, observed Super Typhoon Sanba on September 13 (Figure 1), one day before it strengthened into a Category 5 Typhoon. Fig. 1 clearly shows the mature eye of Sanba. This image has also been made available from NASA (link to) and other sites (“Typhoon Sanba eyes Okinawa, Japan, and South Korea”). AIRS data is archived and distributed by the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC).
Figure 1. AIRS Level-1B brightness temperature at 11.08 µm on September 13, 2012, 04:47:23Z, showing a mature eye in Super Typhoon Sanba. (Click to view full-size).
The corresponding visible/near-IR image (Figure 2) illustrates the wide coverage of the spiraling cloud bands associated with the particularly cold cloud top temperatures displayed in Figure 1. After hitting the island of Okinawa southwest of Japan, Sanba made landfall on the Korean Peninsula as a Category 3 typhoon on September 17.
Figure 2. AIRS Level-1B false color image from visible/near-IR channels on September 13, 2012, 04:47:23Z. Note the wide coverage of the spiral cloud bands associated with the particularly cold cloud top temperatures displayed in Figure 1. (Click to view full-size).
The AIRS mission is to support climate research and improve weather forecasting by producing high resolution atmospheric profiles. Figure 3 shows the cloud fraction and cloud top pressure for the same region shown in Figure 1. Sanba’s deepening eye over open ocean waters can be observed by the cloud top pressure change, from about 700 mb over the eye to about 150 mb surrounding the eye.
Figure 3. AIRS Level-2 cloud fraction and cloud top pressure on September 13, 2012, 04:47:23Z. Sanba’s deepening eye over open ocean waters can be observed by the cloud top pressure change, from about 700 mb over the eye to about 150 mb surrounding the eye. (Image is shown full-size.)
Studies have shown that assimilation of AIRS data improves numerical model prediction and simulation, especially over the ocean where ground observations are sparse. Figures 4 and 5 are animations of five day, 24-hour forecasts from the NOAA National Center for Environmental Prediction operational Global Forecast System model (NOAA/NCEP GFS) and the NASA Global Modeling and Assimilation Office Goddard Earth Observing System Model Version 5 (NASA/GMAO GEOS-5), respectively. Both models assimilated AIRS data and provided good predictions of the actual track of Typhoon Sanba (Figure 6).
Figure 4. Animation of 24-hour forecast from September 13, 2012 to September 19, 2012 from the operational NOAA/NCEP GFS model. This model assimilates AIRS data, and it predicted the track of Typhoon Sanba well. (Animation is shown full-size).
Figure 5. Animation of 24-hour forecast from September 13, 2012 to September 19, 2012 from the NASA/GMAO GEOS-5 model. This model also assimilates AIRS data, and it too provided a a good prediction for Typhoon Sanba’s track. (Animation is shown full-size).
Figure 6. Actual track of Typhoon Sanba. The dates shown on the figure are incorrect; the actual dates for Typhoon Sanba are September 10-17, 2012. Image courtesy of Weather Underground. (Image is shown full-size).
Figure 7 is a 3-day (September 16-19) rainfall accumulation map generated by Giovanni (http://disc.sci.gsfc.nasa.gov/precipitation/tovas/), using the Real-Time Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis data set. This merged TRMM data image indicates more than 200 mm rainfall poured down onto the southern coast of the Korean Peninsula over three days. (Giovanni is a powerful earth data visualization and analysis tool, developed by the NASA GES DISC).
Figure 7. September 16, 2012 00Z to September 19, 2012 00Z accumulated rainfall map generated by Giovanni from the merged TRMM 3B42RT data product. This data visualization shows that more than 200 mm of rainfall poured down onto the southern coast of the Korean Peninsula over three days.
With about ten years of data available, AIRS data (and other complementary datasets) are utilized globally for a broad range of both operational and research uses. AIRS data archived at the NASA GES DISC are available via the Mirador data search and access system (http://mirador.gsfc.nasa.gov/). Many AIRS data products are available for preview via Web-Map Services (WMS), such as those for the Level-3 standard grid and Level-2 Near-Real Time data. AIRS data are also accessible via the NASA Giovanni data system.
Article by Feng Ding, with assistance from GES DISC staff. Editing and Web publication by James Acker.
The GES DISC is a NASA earth science data center, part of the NASA Earth Science Data and Information System (ESDIS) Project.