The winds and currents mission concept

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rodriguez, E., Bourassa, M., Chelton, D., Farrar, J. T., Long, D., Perkovic-Martin, D., & Samelson, R. The winds and currents mission concept. Frontiers in Marine Science, 6, (2019): 438, doi:10.3389/fmars.2019.00438.The Winds and Currents Mission (WaCM) is a proposed approach to meet the need identified by the NRC Decadal Survey for the simultaneous measurements of ocean vector winds and currents. WaCM features a Ka-band pencil-beam Doppler scatterometer able to map ocean winds and currents globally. We review the principles behind the WaCM measurement and the requirements driving the mission. We then present an overview of the WaCM observatory and tie its capabilities to other OceanObs reviews and measurement approaches.ER was funded under NASA grant NNN13D462T. DC was funded under NASA grant NNX10AO98G. JF was funded under NASA grants NNX14AM71G and NNX16AH76G. DL was funded under NASA grant NNX14AM67G. DP-M was funded under NASA grant NNH13ZDA001N. RS was funded under NASA grant NNX14AM66G

Increased Utility of Sea Winds Through Enhanced Calibration

Accurately measuring winds over the surface of the ocean is necessary for improving understanding of the global climate. Sea Winds, a satellite scatterometer, is designed for this purpose. Since its launch it has provided accurate and frequent estimates of near-ocean winds. Due to its success, desires to increase the utility of the data have emerged. These desires, though possible, require performance beyond designed specifications. Additional calibration of the instrument is able to improve instrument performance, allowing development of these emerging applications. Applications include high resolution wind measurement, enhanced resolution imaging, monitoring rain forest destruction, and tracking icebergs and polar ice formation. Improved calibration not only benefits current instruments, but will aid future instruments as well

An Improved Ocean Vector Winds Retrieval Approach Using C- And Ku-band Scatterometer And Multi-frequency Microwave Radiometer Measurements

This dissertation will specifically address the issue of improving the quality of satellite scatterometer retrieved ocean surface vector winds (OVW), especially in the presence of strong rain associated with tropical cyclones. A novel active/passive OVW retrieval algorithm is developed that corrects Ku-band scatterometer measurements for rain effects and then uses them to retrieve accurate OVW. The rain correction procedure makes use of independent information available from collocated multi-frequency passive microwave observations provided by a companion sensor and also from simultaneous C-band scatterometer measurements. The synergy of these active and passive measurements enables improved correction for rain effects, which enhances the utility of Ku-band scatterometer measurements in extreme wind events. The OVW retrieval algorithm is based on the next generation instrument conceptual design for future US scatterometers, i.e. the Dual Frequency Scatterometer (DFS) developed by NASA’s Jet Propulsion Laboratory. Under this dissertation research, an end-to-end computer simulation was developed to evaluate the performance of this active/passive technique for retrieving hurricane force winds in the presence of intense rain. High-resolution hurricane wind and precipitation fields were simulated for several scenes of Hurricane Isabel in 2003 using the Weather Research and Forecasting (WRF) Model. Using these numerical weather model environmental fields, active/passive measurements were simulated for instruments proposed for the Global Change Observation Mission- Water Cycle (GCOM-W2) satellite series planned by the Japanese Aerospace Exploration Agency. Further, the quality of the simulation was evaluated using actual hurricane measurements from the Advanced Microwave Scanning Radiometer and iv SeaWinds scatterometer onboard the Advanced Earth Observing Satellite-II (ADEOS-II). The analysis of these satellite data provided confidence in the capability of the simulation to generate realistic active/passive measurements at the top of the atmosphere. Results are very encouraging, and they show that the new algorithm can retrieve accurate ocean surface wind speeds in realistic hurricane conditions using the rain corrected Ku-band scatterometer measurements. They demonstrate the potential to improve wind measurements in extreme wind events for future wind scatterometry missions such as the proposed GCOM-W2

QuikSCAT Analysis of Hurricane Force Extratropical Cyclones in the Pacific Ocean

Since June 1999, NASA’s Quick Scatterometer Spacecraft (QuikSCAT) has been providing forecasters at the Ocean Prediction Center (OPC) with Near-Real-Time (N.R.T.) surface wind speed and direction data over the world’s oceans. QuikSCAT has allowed forecasters to better predict potential hazards such as storm surges and issue warnings when necessary. Over the past decade, QuikSCAT has received a number of upgrades which improved the forecasters’ abilities to predict the weather more accurately and issue warnings, accordingly. Improvements included the availability of the QuikSCAT data within the forecasters’ workstations starting in October 2001, the introduction of higher resolution satellite data in May 2004, and an improved wind algorithm/rain flag in October 2006. These improvements resulted in an increasing trend in the number of hurricane force extratropical cyclones in each cyclone season, which is not necessarily accurate. Now with four accessible sets of QuikSCAT data (N.R.T. and Science-level 12.5-kilometer and 25-km), the OPC must determine which data set best accurately represents current wind conditions. The goal of the research provided herein is to provide both a quantitative and qualitative analysis of hurricane force extratropical cyclones in the Pacific Ocean. First, using the 12.5-km Science-level data, the number of cyclone events for given storm seasons (September - May) will be determined. Secondly, a comparison of the four QuikSCAT data sets will be made by providing a case-by-case analysis of hurricane force extratropical cyclones. From these two studies, the data of hurricane force extratropical cyclone events for years prior to the implementation of the higher resolution QuikSCAT data and the improved wind algorithm/rain flag can be normalized and forecasters can determine which data set, or combination of data sets, most accurately represents current wind conditions. With the failure of the QuikSCAT satellite in November 2009, the information taken from this research will be valuable for the design and launch of a future satellite

Enabling Big Science in a Small Satellite - The Global L-band Observatory for Water Cycle Studies (GLOWS) Mission

The SMOS and SMAP radiometers have demonstrated the ability to monitor soil moisture and sea surface salinity. It is important to maintain data continuity for these science measurements. The proposed instrument concept (Global L-band active/passive Observatory for Water cycle Studies - GLOWS) will enable low-cost L-band data continuity (that includes both L-band radar and radiometer measurements). The objective of this project is to develop key instrument technology to enable L-band observations using an Earth Venture class satellite. Specifically, a new deployable meta-lens antenna is being developed that will enable a smaller EELV Secondary Payload Adapter (ESPA) Grande-class satellite mission to continue the L-band observations at SMAP and SMOS resolution and accuracy at substantially lower cost, size, and weight. The key to maintaining the scientific value of the observations is the retention of the full 6-meter antenna aperture, while packaging that aperture on a small ESPA Grande satellite platform. The meta-lens antenna is lightweight, has a simplified flat deployed surface geometry, and stows in a compact form factor. This dramatic aperture packaging reduction enables the GLOWS sensor to fit on an Earth Venture class satellite

Laboratory calibration of AAFE radiometer/scatterometer (RADSCAT)

A brief description of the electrical and mechanical instrument configuration, followed by an extensive discussion of laboratory tests and results are contained herein. This information is required to provide parameters for data reduction, and a basis for analysis of the measurement errors in data taken with this instrument

EPS/Metop-SG Scatterometer Mission Science Plan

89 pages, figures, tablesThis Science Plan describes the heritage, background, processing and control of C-band scatterometer data and its remaining exploitation challenges in view of SCA on EPS/MetOp-SGPeer reviewe

Advanced Sensors and Applications Study (ASAS)

The present EOD requirements for sensors in the space shuttle era are reported with emphasis on those applications which were deemed important enough to warrant separate sections. The application areas developed are: (1) agriculture; (2) atmospheric corrections; (3) cartography; (4) coastal studies; (5) forestry; (6) geology; (7) hydrology; (8) land use; (9) oceanography; and (10) soil moisture. For each application area. The following aspects were covered: (1) specific goals and techniques, (2) individual sensor requirements including types, bands, resolution, etc.; (3) definition of mission requirements, type orbits, coverages, etc.; and (4) discussion of anticipated problem areas and solutions. The remote sensors required for these application areas include; (1) camera systems; (2) multispectral scanners; (3) microwave scatterometers; (4) synthetic aperture radars; (5) microwave radiometers; and (6) vidicons. The emphasis in the remote sensor area was on the evaluation of present technology implications about future systems