Merged Satellite Microwave Radiometer Data Products for Climate Studies

Satellite microwave observations provide nearly three decades of continuous, accurate monitoring of surface winds, columnar water vapor, cloud liquid water and rain rates over the global oceans. These very valuable observations are obtained from a number of satellite sensors: SSM/I F08 through F15, SSMIS F16 and F17, AMSR-E, AMSR2, TMI, WindSat, and most recently GMI. The data from these instruments have been carefully intercalibrated at the brightness temperature level, consistently processed and released as RSS Version-7 ocean products. Given the enormous amount of data, using these observations for climate research and model evaluation is time-consuming and proper quality control is non-trivial. We have therefore developed climate products for use by climate researchers. Monthly gridded products are created merging the high-quality RSS Version-7 data from all available instruments. Important aspects of the merging methodology include: selection of input data, requirement of minimal data values per grid cell, use of extended area rain flagging, use of extended area ice flagging, averaging method applied, and application of derived merging parameters. The resulting products provide monthly-averaged global gridded maps over the ocean with a 1-deg spatial resolution. The dataset starts in January 1988 and is updated monthly. One netCDF file contains the monthly average time series, monthly climatology, monthly anomaly time series, trend map, and time-latitude array needed for each parameter. Water vapor was the first of these merged data sets (released in early 2013), followed by ocean surface winds in Jan 2014. A rain rate product is almost ready for distribution. We provide examples of these products, comparisons with other data, and an example of using the data for analysis of climate variability and change.