Loading...
Please wait, while we are loading the content...
Similar Documents
Microwave properties of ice-phase hydrometeors for radar and radiometers: sensitivity to model assumptions
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Skofronick-Jackson, Gail Johnson, Benjamin T. Petty, Grant W. |
| Copyright Year | 2012 |
| Description | A simplied framework is presented for assessing the qualitative sensitivities of computed microwave properties, satellite brightness temperatures, and radar reflectivities to assumptions concerning the physical properties of ice-phase hydrometeors. Properties considered included the shape parameter of a gamma size distribution andthe melted-equivalent mass median diameter D0, the particle density, dielectric mixing formula, and the choice of complex index of refraction for ice. We examine these properties at selected radiometer frequencies of 18.7, 36.5, 89.0, and 150.0 GHz; and radar frequencies at 2.8, 13.4, 35.6, and 94.0 GHz consistent with existing and planned remote sensing instruments. Passive and active microwave observables of ice particles arefound to be extremely sensitive to the melted-equivalent mass median diameter D0 ofthe size distribution. Similar large sensitivities are found for variations in the ice vol-ume fraction whenever the geometric mass median diameter exceeds approximately 1/8th of the wavelength. At 94 GHz the two-way path integrated attenuation is potentially large for dense compact particles. The distribution parameter mu has a relatively weak effect on any observable: less than 1-2 K in brightness temperature and up to 2.7 dB difference in the effective radar reflectivity. Reversal of the roles of ice and air in the MaxwellGarnett dielectric mixing formula leads to a signicant change in both microwave brightness temperature (10 K) and radar reflectivity (2 dB). The choice of Warren (1984) or Warren and Brandt (2008) for the complex index of refraction of ice can produce a 3%-4% change in the brightness temperature depression. |
| File Size | 3667803 |
| Page Count | 20 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20140007380 |
| Archival Resource Key | ark:/13960/t7cs0tb4d |
| Language | English |
| Publisher Date | 2012-12-01 |
| Access Restriction | Open |
| Subject Keyword | Microwave Properties Radiometers Ice-phase Hydrometeors Snowfall Ice Particles Microwave Observations Radars/radar Observations Remote Sensing Sensitivity Analysis Backscattering Ice Dielectrics Precipitation Meteorology Microwave Radiometers Hydrometeors Mathematical Models Radiative Transfer Brightness Temperature Particle Density Concentration Doppler Radar Satellite Temperature Reflectance Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
