![]() The percent of normal IRP pentad is then multiplied by the corresponding CHPClim pentad to produce an unbiased gridded estimate, with units of millimeters per pentad, called the Climate Hazards Group IR Precipitation (CHIRP). These unitless values represent variations in time from the long-term mean (below normal, normal, or above normal). The IRP pentads are then expressed as percent of normal by dividing the values by their long-term (1981–2012) IRP means. First, IR Precipitation (IRP) pentad rainfall estimates are created from satellite data by calculating the percentage of time during the pentad that the IR observations indicate cold cloud tops (<235° K), and converting that value into millimeters of precipitation by means of previously determined local regression with TRMM 3B42 precipitation pentads. The pentad is the focus of the CHIRPS estimation process because sub-monthly time steps are needed for monitoring and modeling agricultural drought (Verdin and Klaver, 2002 Funk and others, 2014).ĬHIRPS is the product of a two part process. All the data sources were compiled as 5-day rainfall accumulations. The main data sources used in the creation of CHIRPS are: (1) the monthly precipitation climatology, CHPClim, temporally disaggregated at each grid cell location into 72 pentadal long-term average accumulation values, in millimeters-these 72 mean values describe the expected annual sequence of rainfall at each location (2) quasi-global geostationary thermal infrared (IR) satellite observations from two NOAA sources, the Climate Prediction Center IR product (0.5 hour temporal resolution, 4 km spatial resolution, for 2000–present) and the National Climatic Data Center IR product (3 hour temporal resolution, 8 km spatial resolution, for 1981–2008) (Janowiak and others, 2001 Knapp and others, 2011) (3) the Tropical Rainfall Measuring Mission (TRMM) 3B42 product from NASA (Huffman and others, 2007 Huffman and others, 2011) (4) atmospheric model rainfall fields from the NOAA Climate Forecast System, version 2 (CFSv2) (Saha and others, 2010 Environmental Modeling Center, 2011) and (5) in situ precipitation observations obtained from a variety of sources including national and regional meteorological services. As of February 12th, 2015, version 2.0 of CHIRPS is complete and available to the public. By combining high resolution (0.05°) rainfall mean fields with current satellite-derived rainfall estimates, the Climate Hazards Group InfraRed Precipitation with Stations (CHIRPS) estimates provide daily, pentadal* (5-day), dekadal (10-day), and monthly precipitation fields suitable for crop monitoring. This information is used to evaluate food security conditions in different parts of the world. The Famine Early Warning Systems Network (FEWS NET) uses satellite rainfall estimates as inputs for monitoring agricultural food production. We are an equal opportunity employer: EOE AA/M/F/Vets/Disability.Product Documentation Climate Hazards Group InfraRed Precipitation with Stations We offer competitive compensation and benefits and are searching for innovative people to join our teams. Tetra Tech combines the resources of a global, multibillion dollar company with local, client-focused delivery in over 450 locations around the world. We are proud to be home to leading technical experts in water, environment, infrastructure, resource management, energy, and international development. Our reputation rests on the technical expertise and dedication of our employees - 21,000 people working together across disciplines and time zones to provide smart, sustainable solutions for challenging projects. Tetra Tech is a leading provider of consulting, engineering, and technical services worldwide. ![]() Tetra Tech’s employees work together to comply with all applicable health & safety practices and protocols, including health orders and regulations related to COVID-19 that are mandated by local, state and federal authorities. Applications that do not meet the minimum requirements listed above will not be considered. No phone calls will be accepted.Īt Tetra Tech, health and safety play a vital role in our success. ![]() Incomplete applications and/or corrupt files may delay processing of your application or remove you from consideration. Please ensure that your Cover Letter and CV/Resume are uploaded and submit only the requested documentation as part of your application. Please indicate where you saw Tetra Tech’s IDS ad posted. To be considered applicants must submit the following as part of the online application process:
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