 |
|
| |
Impact of Surface Roughness on AMSR-E Sea Ice Products
Stroeve, J.C.
Markus, T.
Maslanik, J.A.
Cavalieri, D.J.
Gasiewski, A.J.
Heinrichs, J.F.
Holmgren, J.
Perovich, D.K.
Sturm, M.
Cooperative Inst. for Res. in Environ. Sci., Colorado Univ., Boulder, CO
This paper appears in: Geoscience and Remote Sensing, IEEE Transactions on
Publication Date: Nov. 2006
Volume: 44
,
Issue: 11
, Part 1
On page(s):
3103
- 3117
Location: Edinburgh, UK
ISSN: 0196-2892
Digital Object Identifier: 10.1109/TGRS.2006.880619
Current Version Published: 2006-10-30
|
|
|
|
This paper examines the sensitivity of Advanced Microwave Scanning Radiometer (AMSR-E) brightness temperatures (Tbs) to surface roughness by a using radiative transfer model to simulate AMSR-E Tbs as a function of incidence angle at which the surface is viewed. The simulated Tbs are then used to examine the influence that surface roughness has on two operational sea ice algorithms, namely: (1) the National Aeronautics and Space Administration Team (NT) algorithm and (2) the enhanced NT algorithm, as well as the impact of roughness on the AMSR-E snow depth algorithm. Surface snow and ice data collected during the AMSR-Ice03 field campaign held in March 2003 near Barrow, AK, were used to force the radiative transfer model, and resultant modeled Tbs are compared with airborne passive microwave observations from the Polarimetric Scanning Radiometer. Results indicate that passive microwave Tbs are very sensitive even to small variations in incidence angle, which can cause either an over- or underestimation of the true amount of sea ice in the pixel area viewed. For example, this paper showed that if the sea ice areas modeled in this paper were assumed to be completely smooth, sea ice concentrations were underestimated by nearly 14% using the NT sea ice algorithm and by 7% using the enhanced NT algorithm. A comparison of polarization ratios (PRs) at 10.7, 18.7, and 37 GHz indicates that each channel responds to different degrees of surface roughness and suggests that the PR at 10.7 GHz can be useful for identifying locations of heavily ridged or rubbled ice. Using the PR at 10.7 GHz to derive an "effective" viewing angle, which is used as a proxy for surface roughness, resulted in more accurate retrievals of sea ice concentration for both algorithms. The AMSR-E snow depth algorithm was found to be extremely sensitive to instrument calibration and sensor viewing angle, and it is concluded that more work is needed to investigate the sensitivity of the gradient ratio at 37 a- - nd 18.7 GHz to these factors to improve snow depth retrievals from spaceborne passive microwave sensors
|
|
|
|
Index
Terms
Available to subscribers and IEEE members. |
|
|
|
References
Available to subscribers and IEEE members. |
|
|
|
Citing Documents
Available to subscribers and IEEE members. |
|
|
Cart
