Remote Sensing of Radiative Fluxes and Heating Rates from Satellite Instrument Measurements

Citation

Feldman, Daniel Robert (2008) Remote Sensing of Radiative Fluxes and Heating Rates from Satellite Instrument Measurements. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/XMMC-F033. https://resolver.caltech.edu/CaltechETD:etd-05222008-234331

Abstract

Weather and climate models are required to calculate radiative fluxes and shortwave heating and longwave cooling rate profiles on a large scale. Heating and cooling rates describe the effect that different configurations of temperature, radiatively active gases, and clouds have on the rates of interlayer energy exchange and affect circulation patterns. Meanwhile, a suite of satellite-based instruments from the NASA Earth Observing System’s A-Train provide an unprecedented set of measurements that can be used to produce quantities that can also yield radiative fluxes and heating and cooling rates. This work explores the extent to which passive-infrared hyperspectral measurements such as those made by the Atmospheric Infrared Sounder impart information towards infrared cooling rates. Several novel methods are explored for interpreting and retrieving cooling rates using spectral measurements.

For scenes with optically thick clouds, however, passive visible and infrared measurements will have limited power in describing heating and cooling rates. Vertical cloud information can be obtained from several A-Train instruments: the Microwave Limb Sounder Ice Water Content product provides data on the profiles of ice clouds in the upper troposphere and this work explores how this data can be used to describe the cloud radiative effect. Recently, active-sounding measurements from CloudSat have offered an unrivalled description of cloud profiles which can be used to compute fluxes and heating rates. Preliminary CloudSat products are evaluated and a case study of heating rate analysis is presented in which CloudSat products are used to determine Tropical Tropopause Layer radiation balance.

The radiative processes that affect the far-infrared (wavelengths of 15–100 μm) are described in a limited fashion by the current suite of A-Train measurements, and yet these spectral regions have a large impact on cooling rates in the troposphere. The extra information gained by the introduction of a set of spectrally resolved far-infrared measurements is discussed for clear and cloudy scenes.

Finally, this work discusses future directions for analyzing heating rates derived from remote sensing measurements, and challenges and opportunities for future research.

Thesis Files