WATER DATA FOR TEXAS
The U.S. Drought Monitor, established in 1999, is a weekly map of drought conditions that is produced jointly by the National Oceanic and Atmospheric Administration, the U.S. Department of Agriculture, and the National Drought Mitigation Center (NDMC) at the University of Nebraska-Lincoln. The U.S. Drought Monitor website is hosted and maintained by the NDMC.
U.S. Drought Monitor maps are released every Thursday at 8:30 a.m. eastern time, and are based on data recorded up to 7 a.m. the preceding Tuesday. The weekly map is based on measurements of climatic, hydrologic and soil conditions, as well as reported impacts and observations from more than 350 contributors around the country. Eleven climatologists from the partner organizations take turns serving as the lead author producing the map each week. The authors examine all the data and use their best judgment to reconcile any variances in what different sources report. The U.S. Drought Monitor is a composite index that includes many indicators.
For more data and information, visit the U.S. Drought Monitor.
Palmer Drought Severity Index (PDSI).
The PDSI is updated weekly by the Climate Prediction Center. It is based on rainfall, temperature and historic data, and is computed based on a complex formula devised by W.C. Palmer in 1965. One advantage of the PDSI is that as a strictly numeric product, PDSI values can be computed back to the beginning of the historic record. Disadvantages of the PDSI are that it is slow to detect quick-onset droughts, and does not reflect snowpack, an important component of water supply in the western United States.
Corp Moisture Index.
The Crop Moisture Index, updated weekly by the Climate Prediction Center, is a derivative of the Palmer Drought Index, designed to reflect quickly changing soil moisture conditions.
Keetch-Byram Drought Index.
Keetch-Byram Drought Index (KBDI) is an index used to determining forest fire potential. The drought index is based on a daily water balance, where a drought factor is balanced with precipitation and soil moisture (assumed to have a maximum storage capacity of 8-inches) and is expressed in hundredths of an inch of soil moisture depletion.
The drought index ranges from 0 to 800, where a drought index of 0 represents no moisture depletion, and an index of 800 represents absolutely dry conditions. Presently, this index is derived from ground based estimates of temperature and precipitation derived from weather stations and interpolated manually by experts at Texas A&M Forest Service (TAMFS) for counties across the state. Researchers at Texas A&M University are working with TAMFS to derive this index from AVHRR satellite data and NEXRAD radar rainfall within a GIS.
