scholarly journals Influences of Two-Scale Roughness Parameters on the Ocean Surface Emissivity From Satellite Passive Microwave Measurements

2021 ◽  
pp. 1-12
Author(s):  
Sang-Moo Lee ◽  
Albin J. Gasiewski ◽  
Byung-Ju Sohn
Keyword(s):  
Ocean Surface ◽  
Passive Microwave ◽  
Microwave Measurements ◽  
Surface Emissivity ◽  
Roughness Parameters ◽  
Scale Roughness

scholarly journals A new description of small-scale and large-scale roughness in the fast ocean surface emissivity model

2020 ◽  
Author(s):  
Sang-Moo Lee ◽  
Byung-Ju Sohn
Keyword(s):  
Large Scale ◽  
Incidence Angle ◽  
Ocean Surface ◽  
Small Scale ◽  
Surface Emissivity ◽  
Fresnel Reflection ◽  
Physically Based ◽  
Emissivity Model ◽  
Reflection Theory ◽  
Scale Roughness

AbstractWidely used FAST Microwave Ocean Surface Emissivity Model (FASTEM) does not include the interaction between small-scale and large-scale roughness, which seems to induce errors in the ocean surface emissivity estimation. In this study, we attempt to develop a new model that might be included in the FASTEM-like model. In the developed model, the large-scale roughness is expressed as a function of the local incidence angle (LIA) within the context of Fresnel reflection theory, incorporating the interactions between the small-scale and large-scale roughness into the fast ocean surface emissivity model, as done in the two-scale approach. With the new expression of the large-scale roughness, we also provide a more physically-based form of the equation for the fast ocean surface emissivity calculation that includes the small-scale scattering over a geometrically rough surface. In addition, an algorithm for estimating two-scale roughness from the measured or modeled polarized emissivities in conjunction with the proposed fast ocean surface emissivity equation is provided. The results demonstrate that the interactions between two-scale roughness should be considered in order to estimate accurate two-scale roughness influences on the ocean surface emissivity.

Algorithms for the retrieval of rainfall from passive microwave measurements

1994 ◽  
Vol 11 (1-4) ◽  
pp. 163-194 ◽  
Author(s):  
T. Wilheit ◽  
R. Adler ◽  
S. Avery ◽  
E. Barrett ◽  
P. Bauer ◽  
...  
Keyword(s):  
Passive Microwave ◽  
Microwave Measurements

Multi-Stage Inversion Method to Retrieve Soil Moisture from Passive Microwave Measurements over the Mackenzie River Basin

2013 ◽  
Vol 12 (3) ◽  
pp. vzj2012.0134 ◽  
Author(s):  
Naira Chaouch ◽  
Robert Leconte ◽  
Ramata Magagi ◽  
Marouane Temimi ◽  
Reza Khanbilvardi
Keyword(s):  
Soil Moisture ◽  
River Basin ◽  
Passive Microwave ◽  
Inversion Method ◽  
Microwave Measurements ◽  
Multi Stage ◽  
Mackenzie River Basin ◽  
Mackenzie River

Passive Microwave Measurements Of Sea Surface Roughness During The Saxon Experiment

2005 ◽  
Author(s):  
G.D. Sandlin ◽  
L.A. Rose ◽  
G.L. Geernaert ◽  
J.P. Hollinger ◽  
F.A. Hansen
Keyword(s):  
Surface Roughness ◽  
Passive Microwave ◽  
Sea Surface ◽  
Microwave Measurements ◽  
Sea Surface Roughness

scholarly journals Passive microwave measurements of tundra and taiga snow covers in Alaska, U.S.A.

1993 ◽  
Vol 17 ◽  
pp. 125-130 ◽  
Author(s):  
Matthew Sturm ◽  
Thomas C. Grenfell ◽  
Donald K. Perovich
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Snow Depth ◽  
Marked Reduction ◽  
Basal Layer ◽  
Passive Microwave ◽  
Microwave Measurements ◽  
Effective Emissivity ◽  
Maximum Reduction ◽  
Microwave Emissivity

The microwave emissivity of two snow covers was measured in Alaska in March, 1990. Observations were made on taiga snow near Fairbanks that was 0.83 m thick with a 0.55 m thick basal layer of depth hoar. Other measurements were made on the tundra snow cover at Imnaviat Creek north of the Brooks Range which was 0.27 to 0.64 m thick and consisted of two or more wind slabs overlying a depth hoar layer 0.14 to 0.26 m thick. Density, crystal structure, and grain size were similar in tundra and taiga depth hoar layers.Emissivity was measured at 18.7 and 37 GHz using radiometers mounted on a 1.5 m tall bipod. Measurements were made on undisturbed snow, and then several snow layers were removed and additional measurements were made. This sequence was repeated until all snow had been removed. Effective emissivity values for the full snow depth ranged from 0.6 (37 GHz, H-pol) to 0.95 (18.7 GHz, V-pol) and were similar for both taiga and tundra snow covers. For both snow covers, there was a marked reduction in the effective emissivity (eeff) from that of the underlying ground with a maximum reduction of about 30%. All of the reduction was found to occur within the depth hoar layer. Maximum reduction in eeffcould be caused by a depth hoar layer 0.3 m thick. Overlying wind slab or new snow were nearly “invisible”, increasing the effective emissivity only by a small amount due to self-emittance. Thus, it was difficult to distinguish the two different snow covers on the basis of their emissivity, since both contained 0.3 m of depth hoar or more.

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