![]() ![]() These datasets represent years of careful intercalibration work required to remove spurious sensor-calibration drifts and intersensor biases. OW-CDRs at various stages of development are currently available at a number of institutions. The desired outcome of this process is a consistent time series of global winds, which is referred to as an OW climate data record (OW-CDR). The merger and intercalibration of wind retrievals from many sensors (each having its own unique characteristics) spanning several decades is a formidable engineering and scientific endeavor. OWs are a primary driver of the interaction of the planet's atmosphere and oceans, and a true depiction of decadal wind variability is essential to understanding the Earth's climate. This paper addresses the challenge of combining wind measurements from this large array of sensors into an accurate representation of the variability of OWs over nearly four decades. To present, total of 34 wind-sensing satellite microwave scatterometers and imaging radiometers have been launched. These early missions have been followed by series of advanced sensors. Scatterometer vector wind measurements did not resume until 1991, when the European Space Agency (ESA) launched its European Remote Sensing Satellite-1 (ERS-1). The radiometric wind speed measurements were continued with a second SMMR flown on the Nimbus-7 spacecraft, also launched in 1978. ![]() SeaSat flew the SeaSat-A Scatterometer System (SASS) and the scanning multichannel microwave radiometer (SMMR), but operated for only three months before experiencing a spacecraft power failure. ![]() ![]() Satellite microwave scatterometers and radiometers have been providing measurements of ocean winds (OWs) since the launch of the oceanographic satellite SeaSat in 1978. Specialized model assimilations provide 30-year long high temporal/spatial resolution wind vector grids that composite the satellite wind information from OW-CDRs of multiple satellites viewing the Earth at different local times. A particular future continuity concern is the absence of scheduled new or continuation radiometer missions capable of measuring wind speed. Unfortunately, RapidScat failed in August 2016 and cannot be used to directly calibrate OSCAT-2. Three planned methods of calibrating the OSCAT-2 σ o measurements include 1) direct Ku-band σ o intercalibration to QuikSCAT and RapidScat 2) multisensor wind speed intercalibration and 3) calibration to stable rainforest targets. Extending the OW-CDR into the future requires exploiting all available datasets, such as OSCAT-2 scheduled to launch in July 2016. The ocean wind CDRs (OW-CDRs) are evaluated by comparisons with ocean buoys and intercomparisons among the different satellite sensors and among the different data providers. As an aid to such activities, the various wind datasets are being intercalibrated and merged into consistent climate data records (CDRs). Satellite microwave sensors, both active scatterometers and passive radiometers, have been systematically measuring near-surface ocean winds for nearly 40 years, establishing an important legacy in studying and monitoring weather and climate variability. ![]()
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