Difference between revisions of "Aerosol optical properties"
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== Implementation of optical properties for brown carbon == | == Implementation of optical properties for brown carbon == | ||
| − | '''''This update | + | '''''This update was validated with [[GEOS-Chem_v11-01_benchmark_history#v11-01b|1-month benchmark simulation v11-01b]] and [[GEOS-Chem_v11-01_benchmark_history#v11-01b-Run0|1-year benchmark simulation v11-01b-Run0]]. This version was approved on 19 Aug 2015.''''' |
'''''[mailto:mhammer17@hotmail.com Melanie Hammer] wrote:''''' | '''''[mailto:mhammer17@hotmail.com Melanie Hammer] wrote:''''' | ||
Revision as of 20:45, 19 August 2015
This page describes the aerosol optical properties that are used as input to the GEOS-Chem photolysis mechanisms.
Contents
- 1 Aerosol optical properties update for GEOS-Chem v8-03-01
- 2 Aerosol optical properties at high spectral resolution
- 3 Better representation of OC growth with RH and correction to sulfate optics
- 4 Implementation of optical properties for brown carbon
- 5 Previous issues that have now been resolved
- 6 Known issues
- 7 References
Aerosol optical properties update for GEOS-Chem v8-03-01
Starting with GEOS-Chem v8-03-01, several of the aerosol optical properties for the FAST-J photolysis code (specified in the input file jv_spec.dat have been updated to take into account new observations from various datasets. Colette Heald has created an overview document which describes the implementation of the aerosol optics for FAST-J.
NOTE: For this update there are no modifications to the source code itself, just to the jv_spec.dat file.
Authors
| Name | Affiliation | Date |
|---|---|---|
| Randall Martin | Dalhousie University | 19 November 2009 |
| Colette Heald | Colorado State University | 29 January 2010 |
Overview
The updated jv_spec.dat file was created to reflect current information about aerosol size distributions for sulfate, organic carbon, black carbon and sea salt. The method follows Martin et al., [2003]. Refractive indices are based on GADS. The Mie code is from ftp://ftp.giss.nasa.gov/pub/crmim/spher.f and described in Mischenko et al. [1999]. The current calculation uses an geometric standard deviation (sigma_g) of 1.6 for sulfate, BC and OC following Wang et al. [2003ab] and Drury et al. [submitted]. The sigma_g was also reduced to 1.5 and 1.8 for fine and coarse sea salt respectively following Jaegle et al. [2010]. Specific geometric mean radii (r_g) for each species and relative humidity are in the headers of jv_spec.dat. Consistent aerosol optical properties at 550nm were also created for the file jv_spec_aod.dat.
Some illustrative differences between the "old" jv_spec.dat and the "current" one are given below for 70% relative humidity. The most important change is that organic carbon aerosols are larger in the current version, and that sea salt are substantially smaller.
| Sulfate | Old Value | New Value |
|---|---|---|
| r_g (um) | 0.07 | 0.11 |
| sigma_g | 2.0 | 1.6 |
| r_eff (um) | 0.24 | 0.19 |
| Qext (at 300nm) | 2.4 | 2.6 |
| Qext (at 600nm) | 1.3 | 0.93 |
| Organic Carbon | Old Value | New Value |
| r_g (um) | 0.03 | 0.09 |
| sigma_g | 2.0 | 1.6 |
| r_eff (um) | 0.095 | 0.15 |
| Qext (at 300nm) | 1.2 | 2.3 |
| Qext (at 600nm) | 0.34 | 0.75 |
| Black Carbon | Old value | New value |
| r_g (um) | 0.01 | 0.02 |
| sigma_g | 2.0 | 1.6 |
| r_eff (um) | 0.039 | 0.035 |
| Qext (at 300nm) | 1.06 | 0.95 |
| Qext (at 600nm) | 0.43 | 0.33 |
| Sea salt (accumulation mode) | Old value | New value |
| r_g (um) | 0.38 | 0.15 |
| sigma_g | 2.0 | 1.5 |
| r_eff (um) | 1.32 | 0.23 |
| Qext (at 300nm) | 2.33 | 3.04 |
| Qext (at 600nm) | 2.60 | 1.37 |
| Sea salt (coarse mode) | Old value | New value |
| r_g (um) | 3.2 | 0.73 |
| sigma_g | 2.0 | 1.8 |
| r_eff (um) | 10.1 | 1.7 |
| Qext (at 300nm) | 2.07 | 2.22 |
| Qext (at 600nm) | 2.11 | 2.43 |
The updated jv_spec.dat for v8-02-05 has the following top-of-file header:
jv_spec.dat: FAST-J, FJX (jmao 4/09), Updated AOD's (rvm, clh, 3/10)
Issues
It is likely that organic aerosol at ultraviolet wavelengths is more absorbing than included here as based on GADS [Koepke et al., 1997].
Aerosols are often internally mixed, in contast with their implementation as an external mixture in jv_spec.dat.
--Bob Y. 11:02, 1 March 2010 (EST)
Download location
The updated jv_spec.dat file (and corresponding ratj.d file) are be located in the 1-month benchmark run directory for GEOS-Chem v8-02-05. You may also download them from the following location:
ftp ftp.as.harvard.edu cd pub/geos-chem/data/aerosol_optics/v8-03-01-updates/
These files are now part of the standard GEOS-Chem run directory archive. You may download these with the Git version control software. Please see this wiki post for more information.
--Bob Y. 15:32, 15 November 2010 (EST)
Aerosol optical properties at high spectral resolution
Randall Martin has made available files containing aerosol optical properties at high spectral resolution. These files are not specifically for GEOS-Chem, but they may be useful for some satellite applications or radiative forcing calculations. The files are available from:
- Files compatible with v9-02 (provided by Aaron van Donkelaar)
- ftp://ftp.as.harvard.edu/gcgrid/data/aerosol_optics/hi_spectral_res/v9-02/Hi_Spectral_Res_Files.v9-02.tar.gz
- Previous files
- ftp://ftp.as.harvard.edu/gcgrid/data/aerosol_optics/hi_spectral_res/obsolete/Hi_Spectral_Res_Files_2010.tar.gz
For more information about the data, please see this README file.
--Bob Y. 11:02, 1 March 2010 (EST)
--Melissa Sulprizio 17:18, 17 June 2014 (EDT)
Better representation of OC growth with RH and correction to sulfate optics
This update was tested in the 1-month benchmark simulation v9-02q and approved on 17 Sep 2013. This update is included in Adjoint v35e.
David Ridley wrote:
- I have a couple of updates for GEOS-chem to be included in the next revision.
- These are both changes to the jv_spec.dat and jv_spec_aod.dat, so not the actual code.
- The first change is a better representation of the OC growth with RH for which updated optics have been provided by Randall Martin (oc_reduced_hygroscopicity.dat). The second is a correction to the sulfate optics, by myself, to better represent the water solubility and refractive index (so4_waso.dat). Previously, pure H2SO4 optics were assumed. Now we use the typical water soluble aerosol properties from GADS, similar to ammonium sulfate (higher refractive index but substantially reduced growth factor).
- These changes have been okayed with Colette Heald and Jeff Pierce during discussions last week. If you require any more information please let me know.
Randall Martin wrote:
- The old hygroscopicity for organics in GC (growth factor=1.9 @95% RH) exceeds that of ammonium bisulfate, which was unrealistic. Jiminez et al. (2009) indicates a growth factor closer to 1.35 at 95% RH.
For better representation of OC growth with RH:
36 OC00(rvm) Organic C, RH=00 (n@550=1.53-.006i log-norm: r_g=.07um/sigma=1.6) 300 2.4567 0.127 0.9590 1.000 2.050 2.314 1.944 1.498 1.053 0.721 0.470 400 1.7461 0.127 0.9744 1.000 1.950 2.020 1.529 1.049 0.648 0.396 0.224 550 1.0059 0.127 0.9658 1.000 1.778 1.650 1.068 0.630 0.329 0.174 0.082 600 0.8395 0.127 0.9639 1.000 1.716 1.545 0.948 0.533 0.263 0.132 0.057 1000 0.2405 0.127 0.8509 1.000 1.226 0.978 0.386 0.135 0.035 0.008 0.001 37 OC50(rvm) Organic C, RH=50 (n@550=1.46-.004i log-norm: r_g=.08um/sigma=1.6) 300 2.3664 0.139 0.9709 1.000 2.157 2.549 2.263 1.833 1.360 0.969 0.672 400 1.6538 0.139 0.9816 1.000 2.062 2.254 1.820 1.328 0.878 0.564 0.346 550 0.9462 0.139 0.9748 1.000 1.885 1.855 1.293 0.819 0.464 0.262 0.139 600 0.7904 0.139 0.9732 1.000 1.821 1.739 1.154 0.699 0.378 0.204 0.103 1000 0.2297 0.139 0.8863 1.000 1.323 1.100 0.499 0.207 0.072 0.024 0.006 38 OC70(rvm) Organic C, RH=70 (n@550=1.44-.003i log-norm: r_g=.08um/sigma=1.6) 300 2.3617 0.144 0.9747 1.000 2.191 2.630 2.380 1.964 1.486 1.077 0.761 400 1.6499 0.144 0.9839 1.000 2.100 2.340 1.933 1.443 0.978 0.641 0.403 550 0.9463 0.144 0.9779 1.000 1.925 1.934 1.386 0.901 0.526 0.304 0.166 600 0.7916 0.144 0.9766 1.000 1.862 1.815 1.241 0.772 0.430 0.239 0.125 1000 0.2319 0.144 0.9001 1.000 1.365 1.151 0.547 0.239 0.090 0.033 0.010 39 OC80(rvm) Organic C, RH=80 (n@550=1.43-.003i log-norm: r_g=.09um/sigma=1.6) 300 2.3693 0.149 0.9775 1.000 2.217 2.695 2.476 2.074 1.594 1.172 0.841 400 1.6588 0.149 0.9857 1.000 2.130 2.410 2.029 1.542 1.066 0.711 0.456 550 0.9552 0.149 0.9804 1.000 1.959 2.001 1.467 0.975 0.582 0.343 0.192 600 0.8003 0.149 0.9792 1.000 1.896 1.880 1.317 0.838 0.478 0.271 0.145 1000 0.2364 0.149 0.9111 1.000 1.404 1.196 0.590 0.268 0.107 0.043 0.015 40 OC90(rvm) Organic C, RH=90 (n@550=1.41-.002i log-norm: r_g=.09um/sigma=1.6) 300 2.4065 0.159 0.9818 1.000 2.259 2.802 2.642 2.270 1.793 1.353 0.997 400 1.7001 0.159 0.9885 1.000 2.181 2.532 2.202 1.728 1.235 0.849 0.563 550 0.9903 0.159 0.9843 1.000 2.018 2.123 1.621 1.118 0.696 0.424 0.246 600 0.8328 0.159 0.9834 1.000 1.958 2.000 1.461 0.967 0.576 0.339 0.189 1000 0.2506 0.159 0.9295 1.000 1.476 1.284 0.675 0.326 0.141 0.062 0.025 41 OC95(rvm) Organic C, RH=95 (n@550=1.39-.002i log-norm: r_g=.10um/sigma=1.6) 300 2.4733 0.171 0.9856 1.000 2.296 2.906 2.808 2.476 2.009 1.558 1.180 400 1.7758 0.171 0.9910 1.000 2.229 2.655 2.386 1.933 1.429 1.014 0.696 550 1.0531 0.171 0.9879 1.000 2.079 2.255 1.794 1.286 0.835 0.528 0.319 600 0.8901 0.171 0.9872 1.000 2.022 2.130 1.627 1.122 0.698 0.426 0.248 1000 0.2747 0.171 0.9464 1.000 1.558 1.387 0.776 0.399 0.185 0.087 0.039 42 OC99(rvm) Organic C, RH=99 (n@550=1.36-.001i log-norm: r_g=.12um/sigma=1.6) 300 2.6732 0.203 0.9913 1.000 2.354 3.089 3.121 2.890 2.475 2.026 1.625 400 2.0282 0.203 0.9948 1.000 2.316 2.896 2.769 2.389 1.891 1.431 1.049 550 1.2725 0.203 0.9933 1.000 2.198 2.538 2.193 1.702 1.203 0.819 0.537 600 1.0918 0.203 0.9930 1.000 2.152 2.419 2.018 1.513 1.030 0.680 0.430 1000 0.3631 0.203 0.9722 1.000 1.743 1.645 1.045 0.604 0.316 0.166 0.083
For sulfate optics correction:
22 S00(dar) Trop sulphate, RH=00 (n@550=1.53-0.01i log-norm: r=.07um/sigma=1.6) 300 2.3328 0.121 0.9594 1.000 2.037 2.266 1.874 1.416 0.975 0.655 0.418 400 1.6118 0.121 0.9741 1.000 1.927 1.961 1.452 0.975 0.589 0.354 0.197 550 0.9028 0.121 0.9646 1.000 1.741 1.587 0.996 0.573 0.292 0.153 0.073 600 0.7484 0.121 0.9625 1.000 1.675 1.485 0.882 0.484 0.234 0.118 0.053 1000 0.2108 0.121 0.8417 1.000 1.183 0.959 0.382 0.145 0.049 0.019 0.006 23 S50(dar) Trop sulphate, RH=50 (n@550=1.44 0.00i log-norm: r=.09um/sigma=1.6) 300 2.4175 0.149 0.9752 1.000 2.203 2.666 2.437 2.034 1.557 1.142 0.818 400 1.7099 0.149 0.9844 1.000 2.118 2.386 1.999 1.513 1.041 0.692 0.443 550 0.9931 0.149 0.9788 1.000 1.950 1.984 1.448 0.958 0.570 0.335 0.186 600 0.8352 0.149 0.9776 1.000 1.888 1.864 1.299 0.824 0.468 0.265 0.141 1000 0.2488 0.149 0.9056 1.000 1.405 1.196 0.592 0.272 0.113 0.049 0.020 24 S70(dar) Trop sulphate, RH=70 (n@550=1.41 0.00i log-norm: r=.09um/sigma=1.6) 300 2.4852 0.162 0.9797 1.000 2.251 2.796 2.638 2.274 1.802 1.366 1.012 400 1.7947 0.162 0.9875 1.000 2.177 2.533 2.209 1.739 1.248 0.862 0.574 550 1.0630 0.162 0.9831 1.000 2.023 2.136 1.641 1.138 0.712 0.437 0.255 600 0.8963 0.162 0.9822 1.000 1.966 2.016 1.483 0.988 0.593 0.350 0.197 1000 0.2751 0.162 0.9261 1.000 1.498 1.307 0.697 0.343 0.152 0.070 0.030 25 S80(dar) Trop sulphate, RH=80 (n@550=1.40 0.00i log-norm: r=.10um/sigma=1.6) 300 2.5571 0.174 0.9830 1.000 2.284 2.891 2.789 2.464 2.004 1.558 1.186 400 1.8800 0.174 0.9896 1.000 2.222 2.648 2.381 1.932 1.433 1.019 0.701 550 1.1382 0.174 0.9862 1.000 2.080 2.261 1.805 1.300 0.846 0.537 0.326 600 0.9653 0.174 0.9855 1.000 2.026 2.140 1.642 1.137 0.711 0.435 0.255 1000 0.3040 0.174 0.9408 1.000 1.577 1.407 0.795 0.413 0.193 0.093 0.042 26 S90(dar) Trop sulphate, RH=90 (n@550=1.38 0.00i log-norm: r=.11um/sigma=1.6) 300 2.6967 0.198 0.9875 1.000 2.330 3.033 3.029 2.779 2.356 1.910 1.519 400 2.0587 0.198 0.9927 1.000 2.291 2.836 2.675 2.280 1.782 1.332 0.965 550 1.3021 0.198 0.9906 1.000 2.171 2.477 2.107 1.612 1.121 0.753 0.486 600 1.1172 0.198 0.9901 1.000 2.125 2.359 1.937 1.431 0.958 0.623 0.388 1000 0.3730 0.198 0.9613 1.000 1.716 1.601 0.996 0.566 0.290 0.150 0.074 27 S95(dar) Trop sulphate, RH=95 (n@550=1.36 0.00i log-norm: r=.13um/sigma=1.6) 300 2.8355 0.227 0.9909 1.000 2.362 3.148 3.234 3.069 2.701 2.278 1.889 400 2.2825 0.227 0.9949 1.000 2.344 2.999 2.947 2.625 2.152 1.684 1.281 550 1.5186 0.227 0.9938 1.000 2.252 2.685 2.420 1.960 1.448 1.028 0.703 600 1.3212 0.227 0.9935 1.000 2.213 2.576 2.251 1.767 1.262 0.869 0.575 1000 0.4720 0.227 0.9759 1.000 1.855 1.821 1.243 0.769 0.430 0.239 0.127 28 S99(dar) Trop sulphate, RH=99 (n@550=1.34 0.00i log-norm: r=.18um/sigma=1.6) 300 2.9980 0.304 0.9952 1.000 2.380 3.282 3.494 3.502 3.280 2.972 2.662 400 2.7329 0.304 0.9976 1.000 2.409 3.240 3.385 3.239 2.877 2.444 2.031 550 2.0735 0.304 0.9974 1.000 2.374 3.046 3.015 2.690 2.210 1.731 1.314 600 1.8669 0.304 0.9974 1.000 2.351 2.966 2.873 2.503 2.002 1.530 1.130 1000 0.7986 0.304 0.9914 1.000 2.104 2.302 1.850 1.336 0.875 0.558 0.342
--Melissa Sulprizio 15:14, 16 July 2013 (EDT)
Implementation of optical properties for brown carbon
This update was validated with 1-month benchmark simulation v11-01b and 1-year benchmark simulation v11-01b-Run0. This version was approved on 19 Aug 2015.
Melanie Hammer wrote:
- We have derived optical properties for brown carbon for wavelengths between 200 and 500 nm constrained by satellite measurements of the Ultraviolet Aerosol Index (UVAI), which is a method of detecting absorbing aerosols from satellite retrievals. The optical properties are designed to be easily implemented in GEOS-Chem without additional tracers are required. A switch in the input.geos file selects the optical properties for brown carbon instead of those currently read in for organic carbon. The additional absorption by brown carbon in the ultraviolet results in a decrease in tropospheric OH concentrations by around 20% over biomass burning regions.
--Melissa Sulprizio (talk) 20:37, 8 June 2015 (UTC)
Previous issues that have now been resolved
Fix to jv_spec_aod.dat
This update was tested in the 1-month benchmark simulation v9-02q and approved on 17 Sep 2013. This update is included in Adjoint v35e.
Gabriele Curci wrote:
- I'd like to report a bug in the jv_spec_aod.dat file in the GC run dirs. It contains aerosol optical properties for calculations of AOD at 550 nm, with data that the user manually replace in the jv_spec.dat file.
- The bug is related to dust and consist in missing update of the parameters as done in the jv_spec.dat for other wavelenghts. The update was done some time ago:
- and for dust included updates from Sinyuk et al. (2003):
- Well, the jv_spec.dat is ok, but the companion jv_spec_aod.dat for 550 nm data was not consistently updated for dust.
The current values for dust:
w(nm) Q r-eff ss-alb pi(0) pi(1) pi(2) pi(3) pi(4) pi(5) pi(6) pi(7) 15 Mdust 0.15 = mineral dust (R.V.Martin) 550 1.5356 0.150 0.973 1.000 1.866 1.790 1.223 0.730 0.371 0.187 0.076 16 Mdust 0.25 = mineral dust (R.V.Martin) 550 2.8155 0.250 0.971 1.000 2.029 2.349 2.013 1.596 1.146 0.792 0.505 17 Mdust 0.4 = mineral dust (R.V.Martin) 550 3.0860 0.400 0.956 1.000 1.999 2.546 2.333 2.241 1.897 1.653 1.345 18 Mdust 0.8 = mineral dust (R.V.Martin) 550 2.5841 0.800 0.906 1.000 2.065 2.911 2.965 3.513 3.476 3.796 3.692 19 Mdust 1.5 = mineral dust (R.V.Martin) 550 2.3461 1.500 0.848 1.000 2.298 3.352 3.751 4.627 4.954 5.714 5.983 20 Mdust 2.5 = mineral dust (R.V.Martin) 550 2.2405 2.500 0.788 1.000 2.453 3.638 4.308 5.354 5.998 7.011 7.618 21 Mdust 4.0 = mineral dust (R.V.Martin) 550 2.1744 4.000 0.724 1.000 2.571 3.885 4.822 6.014 6.956 8.157 9.073
Should be changed to:
w(nm) Q r-eff ss-alb pi(0) pi(1) pi(2) pi(3) pi(4) pi(5) pi(6) pi(7) 15 Mdust 0.15 = mineral dust (R.V.Martin) 550 1.5736 0.151 0.993 1.000 1.766 1.248 0.460 0.143 0.027 0.003 0.000 16 Mdust 0.25 = mineral dust (R.V.Martin) 550 3.6240 0.253 0.994 1.000 2.101 2.473 2.097 1.416 0.769 0.355 0.076 17 Mdust 0.4 = mineral dust (R.V.Martin) 550 3.6424 0.402 0.990 1.000 2.005 2.702 2.636 2.714 2.500 2.179 1.787 18 Mdust 0.8 = mineral dust (R.V.Martin) 550 2.6226 0.818 0.971 1.000 2.142 3.213 3.457 4.381 4.388 4.957 4.747 19 Mdust 1.5 = mineral dust (R.V.Martin) 550 2.3682 1.491 0.953 1.000 2.256 3.339 3.617 4.635 4.902 5.843 6.053 20 Mdust 2.5 = mineral dust (R.V.Martin) 550 2.2699 2.417 0.930 1.000 2.357 3.499 3.897 4.971 5.373 6.463 6.862 21 Mdust 4.0 = mineral dust (R.V.Martin) 550 2.1247 3.721 0.897 1.000 2.409 3.562 4.009 5.070 5.556 6.708 7.235
--Melissa Payer 17:11, 8 March 2012 (EST)
Known issues
References
- Drury, E., D.J. Jacob, R.J.D. Spurr, J. Wang, Y. Shinozuka, B.E. Anderson, A.D. Clarke, J. Dibb, C. McNaughton, and R. Weber, Synthesis of satellite (MODIS), aircraft (ICARTT), and surface (IMPROVE, EPA-AQS, AERONET) aerosol observations over North America to improve MODIS aerosol retrievals and constrain surface aerosol concentrations and sources , J. Geophys. Res., submitted.
- Jaegle et al. Global sea salt emissions: New constraints from in situ, AERONET, and MODIS observations, in preparation for submission to Atm. Chem. Phys. Discuss., 2010.
- Koepke, P., M. Hess, I. Schult, and E. P. Shettle, Global Aerosol Data Set, Report No. 243, Max-Planck-Institut fur Meteorologie, Hamburg, ISSN 0937-1060, 1997.
- Martin, R.V., D.J. Jacob, R.M. Yantosca, M. Chin, and P. Ginoux, Global and regional decreases in tropospheric oxidants from photochemical effects of aerosols, J. Geophys. Res., 108, 4097, doi:10.1029/2002JD002622, 2003.
- Mishchenko, M.I., J.M. Dlugach, E.G. Yanovitskij, and N.T. Zakharova, Bidirectional reflectance of flat optically thick particulate layers: an efficient radiative transfer solution and applications to snow and soil surfaces, J. Quant. Spectrosc. Radiat. Transfer, 63, 409-432, 1999.
- Wang, J., S.A. Christopher, F. Brechtel, J. Kim, B. Schmid, J. Redemann, P.B. Russell, P. Quinn, and B.N. Holben, Geostationary satellite rtrievals of aerosol optical thickness during ACE-Asia, J. Geophys. Res., 108, 8657, doi:10.1029/2003JD003580, 2003.
- Wang, J., S.A. Christopher, J.S. Reid, H. Maring, D. Savoie, B.H. Holben, J.M. Livingston, P.B. Russell, and S.K. Yang, GOES-8 retrieval of dust aerosol optical thickness over the Atlantic Ocean during PRIDE, J. Geophys. Res., 108, 8595, doi:10.1029/2002JD002494, 2003.
--Bob Y. 11:02, 1 March 2010 (EST)
