The passage of Hurricane Irene killed at least 55 people, as it blew northward along the East Coast of the United States from the Caribbean Sea through New England. Irene brought tremendous rainfall and wind damage, and left millions of people in the dark due to power outages. Fallen trees caused some power outages to persist for more than a week. Flood damage was particularly extensive in the state of Vermont, with parts of several other coastal states declared disaster areas.
The North American Land Data Assimilation System (NLDAS) Version 2 data, with high spatial and temporal resolutions (0.125° x 0.125° hourly), and various water- and energy-related variables (precipitation, soil moisture, evapotranspiration, latent heat, etc.) is an excellent data source for supporting water and energy cycle investigations. NLDAS can also provide data for case studies of extreme events, such as Hurricane Irene, the July 2011 heat wave in the United States, and the current drought conditions in Texas.
An animation of hourly precipitation data from the NLDAS-2 Primary Forcing product (Figure 1) shows rainfall along the East Coast from Florida to New England hour by hour. The heaviest rainfall was observed at 13Z August 28, 2011 in New York (Figure 2). “Z” refers to Coordinate Universal Time (UTC), also known as Greenwich Mean Time. Three hours later, at 16Z, a burst of very heavy rain fell on central Vermont.
Figure 1. Animation of hourly precipitation (10Z August 26 ~ 12Z August 29, 2011) from NLDAS-2 Primary Forcing product.
Figure 2. NLDAS-2 hourly precipitation at 13Z August 28, 2011.
An area-averaged time series of NLDAS-2 hourly precipitation data (Figure 3) shows three rainfall peaks at 03Z August 27, 2011 for North Carolina, 19Z August 27, 2011 for Virginia, and 13Z August 28, 2011 for New York.
Figure 3: Area-averaged time series of NLDAS-2 hourly precipitation for the U.S. East Coast.
An animation of hourly soil moisture data from NLDAS-2 Mosaic model (Figure 4) shows the surface layer (0-10 cm) soil moisture content changing as Irene swept along the East Coast. It also shows high soil moisture content around 13Z-14Z August 28, 2011 (Figure 5).
Figure 4: Animation of hourly soil moisture (10Z August 26 ~ 12Z August 29, 2011) from the NLDAS-2 Mosaic model.
Figure 5: NLDAS-2 hourly soil moisture at 14Z August 28, 2011.
NLDAS and GLDAS Data Access
To further facilitate access and use of NLDAS and GLDAS data, two new Giovanni data portals, for NLDAS hourly data
and GLDAS 3-hourly data
, have recently been released. Also, the existing Giovanni GLDAS monthly portal has been updated with the appropriately-named GLDAS Version 2 NOAH model data. These new and updated Giovanni portals provide a simple and intuitive way to visualize, analyze, and intercompare GLDAS/NLDAS data without having to download the data.