Variations In Atmospheric Water Vapor Research Articles

Simulation study of multispectral estimation of sea-surface temperature from Infrared observations

A general multispectral analysis technique is described to estimate sea-surface temperature (SST) using data from the High-Resolution Infrared Radiation Sounder (HIRS) on board the TIROS-N/NOAA-6 series of weather satellites. Our study, based on infrared radiative transfer simulations, shows that the radiometric observations for spectral channels at 11.1, 8.3, 13.4, and 4.57 μm are sufficient to provide SST values to a high degree of accuracy. These multispectral calculations automatically incorporate corrections due to the variations in atmospheric water vapor and temperature.

Temporal Variations in Atmospheric Water Vapor and Aerosol Optical Depth Determined by Remote Sensing

By automatically tracking the sun, a four-channel solar radiometer was used to continuously measure optical depth and atmospheric water vapor. The design of this simple autotracking solar radiometer is presented. A technique for calculating the precipitable water from the ratio of a water band to a nearby nonabsorbing band is discussed. Studies of the temporal variability of precipitable water and atmospheric optical depth at 0.610, 0.8730 and 1.04 microns are presented. There was good correlation between the optical depth measured using the autotracker and visibility determined from National Weather Service Station data. However, much more temporal structure was evident in the autotracker data than in the visibility data. Cirrus clouds caused large changes in optical depth over short time periods. They appear to be the largest deleterious atmospheric effect over agricultural areas that are remote from urban pollution sources.

Application of Nimbus 4 THIR 6.7 μm Observations to Regional and Global Moisutre and Wind Field Analyses

The Nimbus 4 temperature-humidity infrared radiometer (THIR) monitors radiation in the 6.5 to 7.2-micron water vapor absorption region with a 23-km spatial resolution at the subsatellite point. Radiation monitored in this spectral region results primarily from emission in the 250 to 500-mb region of the upper troposphere. The THIR 6.7-micron observations are readily available in photofacsimile imagery form which shows very distinctive patterns associated with spatial variations in atmospheric water vapor. These radiometric observations have been combined in several instances with moisture values measured in the upper troposphere by the standard radiosonde network. In each instance, the result is a much more consistent analysis showing increased spatial detail that agrees with the radiometric observations and does not compromise the conventional data. The improved moisture analyses show relatively dry and moist tongues that are very difficult or impossible to infer from the conventional data alone.