Early drought detection in California using satellite-relative humidity data
Tuesday, April 21, 2015
Alireza Farahmand1, Amir AghaKouchak1 and Joao Teixeira2, (1)University of California Irvine, Irvine, CA, United States, (2)Jet Propulsion Laboratory, Pasadena, CA, United States
Abstract:
California has been hit by drought for the past three years, causing significant impacts on the ecosystem, society and economy of the state. Early detection of drought is of particular importance for agriculture and water resource management. The Standardized Precipitation Index (SPI) based on precipitation has been widely used for drought onset detection. Precipitation is not expected in low relative humidity conditions. Thus, in this study, the Standardized Relative Humidity Index (SRHI) based on the NASA Atmospheric Infrared Sounder (AIRS) Relative Humidity has been proposed for drought onset detection in California. The SRHI uses a non-parametric standardization approach that does not require any assumption about the underlying distribution function. Similar to the SPI, the SRHI can be derived for different time scales. In this study, historical values of SRHI are evaluated against SPI to not only identify the locations where SRHI has been the earlier drought detector but also to quantify the lead time of SRHI with respect to SPI in California.
