RSS-Ocean-Surface-Emissivity-Model

Remote Sensing Systems Ocean Surface Emissivity Model 6 - 90 GHz

Remote Sensing System Santa Rosa, California

Contact Thomas Meissner [email protected]

September 14, 2022

RSS_RTM_2012 published on GitHub under MIT license

If the RTM plays an essential role in the generation of new research results, please acknowledge/credit RSS and let us know.

FORTRAN 90 module for computing ocean surface emissivity at microwave frequencies Citation: T. Meissner and F. Wentz, RSS Ocean Surface Emissivity Model, doi: 10.21982/M84S3Q.

References: [MW 2004]: T. Meissner and F. Wentz, "The Complex Dielectric Constant of Pure and Sea Water from Microwave Satellite Observations", IEEE Transactions on Geoscience and Remote Sensing, vol 42 (9), 1836-1849, doi: 10.1109/TGRS.2004.831888, 2004.

[MW 2012]: T. Meissner, and F. Wentz, "The Emissivity of the Ocean Surface between 6 - 90 GHz over a Large Range of Wind Speeds and Earth Incidence Angles", IEEE Transactions on Geoscience and Remote Sensing, vol 50 (8), 3004-3026, doi: 10.1109/TGRS.2011.2179662, 2012.

[MWR 2014]: T. Meissner, F. Wentz, and L. Ricciardulli, "The Emission and Scattering of L-band Microwave Radiation from Rough Ocean Surfaces and Wind speed Measurements from Aquarius", Journal of Geophysical Research: Oceans, 119, doi:10.1002/2014JC009837, 2014.

[MWD 2012]: T. Meissner, F. Wentz and D. Draper, "GMI Calibration Algorithm and Analysis Theoretical Basis Document", report number 041912, Version-G, Remote Sensing Systems, Santa Rosa, CA, 124 pp. doi: 10.56236/RSS-au,
https://doi.org/10.56236/RSS-au

Content:

1. readme.mc: This file

2. RSS_RTM__module.f90: FORTRAN 90 module for computing ocean surface emissivity at microwave frequencies.

3. RSS_RTM_driver.f90: FORTRAN 90 sample driver.

4. control_output.txt: Sample control output created by driver routine.

5. external_files: 4 external files (tables).
   finetune_emiss_wind.txt: ASCII fit_emiss_phir_wind.txt: ASCII em0_ref_freq_sst.txt: ASCII mk_scatterm_table_all.zip: ASCII zipped

6. Meissner_TGRS_2012_emissivity.pdf [MW 2012]:
   T. Meissner, and F. Wentz, "The Emissivity of the Ocean Surface between 6 - 90 GHz over a Large Range of Wind Speeds and Earth Incidence Angles", IEEE Transactions on Geoscience and Remote Sensing, vol 50 (8), 3004-3026, doi: 10.1109/TGRS.2011.2179662, 2012.

The code ahs been tested on Intel(R) Parallel Studio XE 2011 Update 1 Copyright (C) 1985-2011 Intel Corporation. All rights reserved. Intel(R) Composer XE 2011 Update 4 (package 196), 32-bit and 64-bit compilers. It should be portable to gfortran.

Release Notes:

The following changes/updates from [MW 2012] are contained in the code.

1. dielectric_meissner_wentz: Typo (sign) in the printed version of coefficient d3 in Table 7. Its value should be -0.35594E-06.
2. dielectric_meissner_wentz: Changed SST behavior of coefficient b2 from: b2 = 1.0 + s*(z(10) + z(11)sst) to b2 = 1.0 + s(z(10) + 0.5z(11)(sst + 30))
3. Introduced SST dependence for wind direction signal similar than eq. (15) in [MW 2012].

Routines:

1. find_surface_tb Master wrapper routine that caclulates all components of the ocean surface emissivity. Output user selected.

2. dielectric_meissner_wentz Dielectric model of sea and pure water [MW 2004], with minor updates in [MW 2012].

3. fdem0_meissner_wentz Caclulates emissivity of specular surface [MW 2004]

4. fd_emiss Calculates emissivity of specular surface (v/h), isotropic wind induced emissivity (v/h) and wind direction signal (v/h/S3/S4) [MW 2012], sections IV + VI.

5. fd_scatterm_all Calculates correction for downwelling scattered atmospheric radiation [MW 2012], section V.

6. fd_tcos_eff Calculates effective cold space temperature taking into account the deviation between Rayleigh-Jeans and Planck law as function of frequency [MWD 2012], Appendix D.

7. get_emiss_wind Calculates isotropic wind induced emissivity at tabulated frequency values and reference EIA of 55.2. [MW 2012], section IV, Table 2.

8. get_aharm_phir Calulates harmonic ocefficients of wind direction signal at tabulated frequency values and reference EIA of 55.2. [MW 1012], section VI, Tables 3 + 4.

9. get_aharm_phir_nad Calculates harmonic ocefficients of wind direction signal at tabulated frequency values at nadir [MW 2012, section VI, eq. (26)]

10. get_sst_fac Precomputed value of E0(SST)/E0(SST_ref=20C) for faster computation [MW 2012], eq. (15)

11. fd_xmea_win Provides wind speed polynomials for [MW 2012], eqs. (14) + (25)