DOI: 10.5061/dryad.4qrfj6qhj
title: Water vapor and solar zenith angle dependent absorption tables and radiance calculations

description: The dataset has been generated in order to simulate the impact of
 atmospheric water vapor and solar zenith angle on the in-water heating
 profile.  The 1 cm-1 resolution calculations are convolved with
 high-resolution in-water absorption from Segelstein (1981) in order to
 calculate the effect of shifting absorption weightings due to atmospheric
 water vapor.  These values are then integrated over 9 discrete
 spectral bands that match those of the widely used Paulson &
 Simpson (1981) scheme, partitioned in terms of total column atmospheric
 water vapor and solar zenith angle.  The end results are
 described in the GRL manuscript.
description: The dataset has been generated using a globally representative
 set of 1,358 atmospheric profiles sampled from ERA-40 input to MODTRAN4
 run at 1 cm<sup>-1</sup> resolution, with a wavenumber range
 of 500 - 40,000 cm<sup>-1</sup>.  Details are given in the
 README file.
description: # Solar radiances
 [https://doi.org/10.5061/dryad.4qrfj6qhj](https://doi.org/10.5061/dryad.4qrfj6qhj) Modtran calculations of surface solar irradiance at 1 cm-1 resolution (500 - 40,000 cm-1) for 1,358 globally representative ocean atmospheres sampled from ERA-40. Various angles are simulated, corresponding to sec(solar_zenith_angle) values of 1, 1.5, 2, 3, 5 & 10 (approximately 0, 48, 60, 70, 78 & 84 degrees). ## Description of the data and file structure ***Format of files*** The 9-band solar zenith angle dependent tables for solar Planck weight and in-water absorption are in `revised_morel_fracs_tcwv_sza.txt` and `revised_depth_fracs_tcwv_sza.txt` respectively. The tables are organized by increasing solar zenith angle, with '`00`' being the Sun overhead. The other number is *sec*(sza) and is the exact quantity (the solar zenith angle is only quoted to the nearest degree). The organization of each individual table is as follows: \ &lt;#*profiles(1)&gt; \ &lt;#_profiles(2)&gt; . . . \ &lt;#_profiles(13)&gt; where band_i(j) is the data for band_i of the 9-band model for the corresponding mean TCWV amount mean(TCWV(j)) in kg.m-2. For the solar Planck weights, the data values are the fraction of the net solar radiation at the water surface and therefore will sum to unity (last column). The in-water absorption values are 1/*e* depths in meters, with the shortest wavelength band (band_1) being ~27 meters and all but one of the rest being &lt;&lt;1 meter, thus the sum is a somewhat arbitrary value between ~27 m and ~30 m. Note that the in-water absorption values in these tables have not yet been scaled to account for refraction - that adjustment is done inside the diurnal warming model code. Modtran output files (1,358 profiles x 6 angles) are contained in a single tar file `era99_t_s_tape7_files.tar.gz`. Once extracted, the `.tp7` output files are in standard "TAPE7" ASCII format. Output is 1 cm-1 resolution (columns are labeled in the ASCII file). File names are constructed as *era99_**t+s**.tp7* where is 2-digit solar zenith angle to nearest degree and runs from 1 -&gt; 1358. The corresponding total column water vapor amounts for each of the 1,358 profiles is contained in `era.99.tpw` The Segelstein high-resolution in-water absorption data are contained in ASCII file `segelstein81_nm_1overE(cm).txt` and contains values for the wavelength in nanometers and the 1/*e* depth in centimeters. # Sharing/Access information Input atmospheric data was derived/sampled from the following sources: * [https://www.ecmwf.int/en/forecasts/dataset/ecmwf-reanalysis-40-years](https://www.ecmwf.int/en/forecasts/dataset/ecmwf-reanalysis-40-years) ## Code/Software MODTRAN4 uses "TAPE5" input files. Summary information of the input cards showing the model configuration for each run is provided in the first part of the `*.tp7` output files. *N.B.* The latest version of Modtran is MODTRAN6 [http://modtran.spectral.com/](http://modtran.spectral.com/)