Engineering topics

Fitzjarrald, Daniel E.

Publications and source records attributed to Fitzjarrald, Daniel E..

6 records

NASA NTRS1993

Global water cycle

This research is the MSFC component of a joint MSFC/Pennsylvania State University Eos Interdisciplinary Investigation on the global water cycle extension across the earth sciences. The primary long-term objective of this investigation is to determine the scope and interactions of the global water cycle with all components of the Earth system and to understand how it stimulates and regulates change on both global and regional scales. Significant accomplishments in the past year are presented and include the following: (1) water vapor variability; (2) multi-phase water analysis; (3) global modeling; and (4) optimal precipitation and stream flow analysis and hydrologic processes.

Robertson, Franklin↗

NASA NTRS1993

A modeling study of marine boundary layer clouds

Marine boundary layer (MBL) clouds are important components of the earth's climate system. These clouds drastically reduce the amount of solar radiation absorbed by the earth, but have little effect on the emitted infrared radiation on top of the atmosphere. In addition, these clouds are intimately involved in regulating boundary layer turbulent fluxes. For these reasons, it is important that general circulation models used for climate studies must realistically simulate the global distribution of the MBL. While the importance of these cloud systems is well recognized, many physical processes involved in these clouds are poorly understood and their representation in large-scale models remains an unresolved problem. The present research aims at the development and improvement of the parameterization of these cloud systems and an understanding of physical processes involved. This goal is addressed in two ways. One is to use regional modeling approach to validate and evaluate two-layer marine boundary layer models using satellite and ground-truth observations; the other is to combine this simple model with a high-order turbulence closure model to study the transition processes from stratocumulus to shallow cumulus clouds. Progress made in this effort is presented.

Wang, Shouping↗

NASA NTRS1988

Global measurements of wind fields using the Laser Atmospheric Wind Sounder (LAWS) on the Earth Observing System (EOS)

The technology for measuring global wind fields in space by the Laser Atmospheric Wind Sounder (LAWS) to be flown on the Earth Observing System (EOS) is discussed. Studies initiated by NASA to determine the feasibility of using Doppler lidar from a platform in space to measure the wind globally have shown the general feasibility of the technique and have identified the technological problems that need to be resolved. Among the lidar systems being evaluated, CO2 coherent detection lidar is given special consideration. A comprehensive research program, the Global Backscatter Experiment, has been established to study global distribution of naturally occurring atmospheric aerosols that provide signal return at the wavelengths used by the techniques under consideration. Wind profiles from space will provide essential information for advancing the skill of numerical weather prediction, furthering the present knowledge of the large-scale atmospheric circulation and climate dynamics, and of global biogeochemical and hydrologic cycles.

Fitzjarrald, Daniel E.↗

NASA NTRS1988

Doppler lidar wind measurements on the EOS - LAWS

This paper discusses the efforts currently underway to prepare for the deployment of the Laser Atmospheric Wind Sounder (LAWS) instrument on an Earth Observing System (EOS) polar orbiter and on the Space Station. Attention is given to the measurement techiques, which include ground-based and airborne measurements in the atmosphere, and to the scientific and the technical issues being addressed. Global wind profiles obtained with the LAWS will effect dramatic improvement in numerical weather prediction and will be useful in determining the midtroposphere steering currents that are important in hurricane track forecasts. The global wind data will also provide information on large-scale atmospheric circulation and climate dynamics and on biogeochemical and hydrologic cycles.

Fitzjarrald, Daniel E.↗

NASA NTRS1987

Mauna Loa Aerosol Backscatter Intecomparison Experiment (MABIE)

Measurements of CO2 aerosol backscatter coefficients and other aerosol physicochemical properties were obtained in remote Pacific free tropospheric airmasses at the Mauna Loa Observatory in Hawaii. The experiment used an attenuated total reflection impactor (Johnson et al., 1983), a dispersive infrared spectrophotometer, and a high-resolution optical particle counter. Preliminary results suggest that sulfate compounds dominate background backscatter properties at CO2 wavelengths between 9 and 10 microns.

Bowdle, David A.↗

NASA NTRS1987

Lidar technology measurements and technology: Report of panel

Lidar is ready to make an important contribution to tropospheric chemistry research with a variety of spaceborne measurements that complement the measurements from passive instruments. Lidar can now be considered for near-term and far-term space missions dealing with a number of scientifically important issues in tropospheric chemistry. The evolution in the lidar missions from space are addressed and details of these missions are given. The laser availability for space missions based upon the technical data is assessed.

Browell, Edward V.↗