26. Assessing the Surface Contribution in Passive Microwave
Measurements for Physical Retrieval of Precipitation
Author：
Sarah Ringerud
Affiliation： Colorado State University
In the GPM era, physical retrievals of precipitation over land using passive
microwave radiometers will require the ability to separate emission contributions
from the atmosphere from those of the surface. This requires information about the
nature of the surface, it’s dynamic properties, and the effective result of these
(along with their heterogeneity) as viewed from the space borne sensor. In an effort
to gain insight into these parameters and how they might effect future physical
retrievals of precipitation, three datasets are assembled for analysis. Oklahoma is
chosen as a study area so as to utilize it’s high-density network of available
observations. Nine years of clear sky satellite emissivity retrievals are performed
over the region using AMSR-E satellite overpasses. Retrieved values are compared
with 9 years of modeled values compiled from a combination of land surface model
results and a forward emissivity model. Brightness temperatures computed from
each will then be compared to the observations. In addition, data from the recent
MC3E field campaign over the region will be analyzed comparing brightness
temperatures measured using instruments above the ER2 high altitude aircraft with
coincident surface measurements. Results will be interpreted in terms of their
correlation to surface parameters such as soil type, soil moisture, and vegetation, in
an attempt to pinpoint information that will be necessary for a future physical
precipitation retrieval for passive microwave sensors.