Milton Halem

An Assessment of the FGGE Satellite Observing System during SOP-1

This study investigates the degree to which data from the space-borne FGGE observing systems are able to determine the complete state of the atmosphere when incorporated into a global objective analysis cycle. Three data assimilation experiments are performed with the Goddard Laboratory for Atmospheric Sciences (GLAS) analysis/forecast system, using different combinations of the FGGE level II–b data collected during the first Special Observing Period (SOP-1), 5 January through 5 March 1979. The control experiment is an assimilation cycle with the complete FGGE II–b data. The other two assimilation/forecast experiments consist of i) the conventional system without the satellite data and special FGGE data sets; and ii) the FGGE II–b surface and satellite temperature soundings and cloud-track winds, aircraft data, and special FGGE data sets, but without the conventional rawinsonde/pilot balloon network. From these experiments, we attempt to assess the accuracy of the inferred mass and motion fields over data...

Impact Of Satellite Temperature Sounding And Wind Data On Numerical Weather Prediction

A brief review is presented of simulation studies and real-data experiments that were conducted to assess the impact of satellite observations on numerical weather prediction. These experiments show that while there has been some redundancy between observing systems, satellite data have made significant contributions toward improving global forecasting.

Simulation studies and the design of the First Garp Global Experiment.

Simulation studies have played an increasingly important role in planning for the First GARP Global Experiment (FGGE) during the last two years by providing information on the meteorological impact of various untested or incompletely tested elements of the GARP observing system. The studies are intended to provide information to FGGE planners on the capabilities of alternature systems for meeting a specific FGGE requirement. The simulation studies also provide a valuable input to cost-effectiveness studies by indicating tradeoffs of one possible type of observing platform against another, such as constant-level balloons vs buoys. These tradeoffs can lead to major gains in research yield per dollar of expenditure on the observing system.

Scientific computing challenges arising from space-borne observations

Five supercomputing problems are described: (1) determining the motions of the Earths inner core boundary from outer-space measurements of the magnetic field; (2) simulating the global dynamics of the Earths ocean currents, sea-ice cycles, land surface biology, and interannual atmospheric climates; (3) upper atmospheric chemistry; (4) modeling solar flare eruptions; and (5) the role of jet processes in the birth of stars. In addition, two examples indicating the growing importance of the use of supercomputers for scientific visualization are presented. The first deals with remote mapping from space of the Earths topography or other planets. The second problem from astrophysics deals with mapping the cosmic background radiation in the presence of other astronomical signatures. A brief overview of interdisciplinary modeling plans under development for the next generation of supercomputers is given. >

Analysis of GARP data requirements

Global atmospheric research program data requirements analysis based on two level numerical model

Chapter 5 - A Retrospective Analysis of the Pioneering Data Assimilation Experiments with the Mintz – Arakawa General Circulation Model

This chapter discusses the retrospective analysis of the pioneering data assimilation experiments with the Mintz–Arakawa general circulation model, which have a profound impact on satellite meteorology. The basic objective of observing-system simulation studies is the determination of the relationship between the temperature errors and the inferred global winds and pressures, for realistic configurations of a proposed earth observing system with advanced vertical temperature sounders. Numerical results obtained with the Goddard Earth Observing System (GEOS) general circulation models (GCM) indicate that if a continuing day-by-day sequence or history of temperature profiles is inserted into the numerical integrations at appropriate time intervals, wind components and sea-level pressure can be determined to a useful degree of accuracy. GCMs of higher spatial and vertical resolution assimilate temperature data to substantially improve the inferred winds and sea-level pressure where no data are available. Assimilating surface pressure greatly improves the rate of adjustment and the asymptotic accuracies of the extratropical winds, but does not significantly improve the inferred tropical winds.

Review of experiments on the impact of satellite data on numerical weather prediction

A brief review is presented of simulation studies and real data experiments which were conducted to assess the impact of satellite observations on numerical weather prediction. These experiments show that while there has been some redundancy between observing systems, satellite data has made significant contributions toward improving global forecasting.

Cloud field assimilation using simulated Triana satellite data

Abstract In the next few years, NASA plans to launch satellite Triana, a deep space Earth observatory that will take a full-disk view of the sunlit side of the Earth. Triana carries two instruments, EPIC, which will deliver Science products such as total precipitable water, cloud height, aerosol index, total ozone, and a global visible cloud field image, and NISTAR, which obtains precise radiometry integrated over the entire sunlit disk. Using a contemporary atmospheric model (namely the Eta model), we have started a project whose goal is to simulate some of the Triana observations and to assess the impact of Triana data for weather and climate predictions. In this paper, we report on the results of numerical experiments assimilating temperature profiles with and without cloud liquid water for inferring tropical and extra-tropical atmospheric states. We also assess the impact of initializing cloud liquid water for short term forecasts and data assimilation cycles.