Christopher M. Hayden

Upper-tropospheric winds derived from geostationary satellite water vapor observations

The coverage and quality of remotely sensed upper-tropospheric moisture parameters have improved considerably with the deployment of a new generation of operational geostationary meteorological satellites: GOES-8/9 and GMS-5. The GOES-8/9 water vapor imaging capabilities have increased as a result of improved radiometric sensitivity and higher spatial resolution. The addition of a water vapor sensing channel on the latest GMS permits nearly global viewing of upper-tropospheric water vapor (when joined with GOES and Meteosat) and enhances the commonality of geostationary meteorological satellite observing capabilities. Upper-tropospheric motions derived from sequential water vapor imagery provided by these satellites can be objectively extracted by automated techniques. Wind fields can be deduced in both cloudy and cloud-free environments. In addition to the spatially coherent nature of these vector fields, the GOES-8/9 multispectral water vapor sensing capabilities allow for determination of wind fields over multiple tropospheric layers in cloud-free environments. This article provides an update on the latest efforts to extract water vapor motion displacements over meteorological scales ranging from subsynoptic to global. The potential applications of these data to impact operations, numerical assimilation and prediction, and research studies are discussed.

Fully Automated Cloud-Drift Winds in NESDIS Operations

Abstract Cloud-drift winds have been produced from geostationary satellite data in the Western Hemisphere since the early 1970s. During the early years, winds were used as an aid for the short-term forecaster in an era when numerical forecasts were often of questionable quality, especially over oceanic regions. Increased computing resources over the last two decades have led to significant advances in the performance of numerical forecast models. As a result, continental forecasts now stand to gain little from the inspection or assimilation of cloud-drift wind fields. However, the oceanic data void remains, and although numerical forecasts in such areas have improved, they still suffer from a lack of in situ observations. During the same two decades, the quality of geostationary satellite data has improved considerably, and the cloud-drift wind production process has also benefited from increased computing power. As a result, fully automated wind production is now possible, yielding cloud-drift winds whos...

GOES-VAS Simultaneous Temperature-Moisture Retrieval Algorithm

Abstract Vertical soundings of temperature and moisture derived from the GOES VISSR Atmospheric Sounder (VAS) measurements have been produced operationally since summer 1987 at the VAS Data Utilization Center (VDUC). The algorithm which was developed for the VDUC is described here in detail. Tunable features are identified, and their sensitivities are shown. The algorithm is used to process a case study for 6 March 1982 to examine its capability in a rapidly evolving weather pattern. Weaknesses are exposed, in particular the bias errors in the retrievals and the dependence on first guesses, but strengths are also evident, namely, the capacity to refine gradients and patterns in a manner which improves the first guesses.

The impact of satellite-derived winds on numerical hurricane track forecasting

Abstract While qualitative information from meteorological satellites has long been recognized as critical for monitoring tropical cyclone activity, quantitative data are required to improve the objective analysis and numerical weather prediction of these events. In this paper, results are presented that show that the inclusion of high-density, multispectral, satellite-derived information into the analysis of tropical cyclone environmental wind fields can effectively reduce the error of objective track forecasts. Two independent analysis and barotropic track-forecast systems are utilized in order to examine the consistency of the results. Both systems yield a 10%–23% reduction in middle- to long-range track-forecast errors with the inclusion of the satellite wind observations.

Derived Product Imagery from GOES-8

Abstract Derived product imagery (DPI) is a method of presenting quantitative meteorological information, derived from satellite measurements, as a color-coded image at single-pixel resolution. Its intended use is as animated sequences to observe trends in the displayed quantities, which for the GOES-8 are total precipitable water, lifted index, and surface skin temperature. Those products are produced once per hour, over the continental United States and the Gulf of Mexico. This paper reviews the development of the DPI and details the algorithm used for GOES-8. The quality of the products is discussed, and an example is given. The greatest value of the DPI probably lies in comparing a sequence of the satellite product with a sequence derived from a numerical forecast. In this way, deviation of the forecast from reality is readily exposed.

First Sounding Results from VAS-D

First results are presented from an experiment to sound the atmospheres temperature and moisture distribution from a geostationary satellite. Sounding inferences in clear and partially cloudy conditions have the anticipated accuracy and horizontal and vertical resolutions. Most important is the preliminary indication that small but significant temporal variations of atmospheric temperature and moisture can be observed by the geostationary satellite sounder. Quantitative assessment of the accuracy and meteorological utility of this new sounding capability must await the accumulation of results over the coming months.

Monthly Mean Large-Scale Analyses of Upper-Tropospheric Humidity and Wind Field Divergence Derived from Three Geostationary Satellites

Abstract This paper describes the results from a collaborative study between the European Space Operations Center, the European Organization for the Exploitation of Meteorological Satellites, the National Oceanic and Atmospheric Administration, and the Cooperative Institute for meteorological Satellite Studies investigating the relationship between satellite-derived monthly mean fields of wind and humidity in the upper troposphere for March 1994. Three geostationary meteorological satellites GOES-7, Moteoset-3, and Meteosat-5 are used to cover an area from roughly 160°W to 50°E. The wind fields are derived from tracking features in successive images of upper-tropospheric water vapor (WV) as depicted in the 6.5-μ absorption band. The upper-tropospheric relative humidity (UTH) is inferred from measured water vapor radiances with a physical retrieval scheme based on radiative forward calculations. Quantitative information on large-scale circulation patterns in the upper troposphere is possible with the dense...

A Note on Water-Vapor Wind Tracking Using VAS Data on McIDAs

Abstract Eleven data sets where water-vapor winds were obtained from the GOES-5 6.7-micrometer measurement over the United States are compared with rawinsondes. Over 2OOO point comparisons are made for: a) an arbitrary height assignment of 400 mb; and b) a height assignment determined by matching the measured brightness temperature to the temperature structure represented in the LFM (Limited Area Fine Mesh) analysis. It is shown that the water vapor winds provide uniform horizontal coverage of midlevel flow with high accuracy (8 mps vector RMS). Furthermore, the radiometric height assignment significantly improves the accuracy.

Determination of Moisture From NOAA Polar Orbiting Satellite Sounding Radiances

Abstract A method is presented for deducing lower troposphere moisture fields from radiances measured by the operational polar orbiting NOAA satellites. Statistical evaluation of the technique demonstrates the viability of the approach. A case study with TIROS-N observations shows substantial improvement over current operational methods, and a qualitatively reasonable product. High moisture gradients are clearly defined and horizontal consistency is achieved. The technique appears useful for the initialization of subsynoptic forecast models.

The Meteorological Satellite: Overview of 25 Years of Operation

The first weather satellite was launched on 1 April 1960. In the 25 years since, weather satellites have contributed to improved weather analyses and forecasts worldwide. As a maturing component of a global observing system, the meteorological satellite promises even greater financial benefits and a higher quality of life to mankind.