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Thompson AA enhancements: BC aerosol, biomass burning emissions, and … (
#1616) TYPE: enhancement KEYWORDS: real, Thompson aerosol-aware, microphysics SOURCE: Timothy W. Juliano and Pedro A. Jimenez (NCAR/RAL) DESCRIPTION OF CHANGES: Problem: Several enhancements have been made to the Thompson Aerosol-Aware microphysics scheme (mp_physics=28) related to the addition of: 1. black carbon (BC) aerosol category from either climatology (e.g., GOCART) or first guess aerosol source (e.g., GEOS-5); 2. biomass burning aerosol (organic carbon (OC) and BC) emissions from a first guess aerosol source (e.g., GEOS-5); 3. time-varying surface emissions from a first guess aerosol source (e.g., GEOS-5) Solution: 1. Addition of a new category (3D scalar variable, QNBCA), that represents BC aerosol for the Thompson Aerosol Aware (AA) microphysics scheme. This variable is handled in a similar fashion as QNWFA and QNIFA (water-friendly and ice-friendly aerosols, respectively), including the surface emissions. In terms of the microphysical activity of QNBCA, at present we consider only its removal due to wet scavenging by rain, snow, and graupel. We recognize that this is a limitation of the current implementation; however, more detailed investigation into the water/ice nucleating abilities of BC are needed and left for future work. As a result of this limitation, activation of BC aerosol is made through the &domains namelist option, wif_input_opt: =1 retains the current meaning (water- and ice-friendly aerosols only) and =2 adds the BC aerosol on top of the water- and ice-friendly aerosols. This allows a user to active the Thompson AA scheme as in its original implementation if desired. To account for the radiative contribution of BC aerosols (which are strongly absorbing compared to the QNWFA and QNIFA aerosols that are strongly scattering) to diagnosed AOD at 550nm, we extend the look-up table in subroutine gt_aod. The new look-up table values are computed using Mie code provided by Trude Eidhammer (NCAR/RAL). For BC, we use the following parameter values: * Modal radius = 11.8 nm following Chin et al. (2002) to maintain consistency with the original implementation of the Thompson AA scheme * Geometric standard deviation = 2.0 following Chin et al. (2002) to maintain consistency with the original implementation of the Thompson AA scheme * Real and imaginary indices of refraction = 1.85 and 0.71, respectively, following Bond et al. (2006) * Hygroscopicity = 0.2 following Engelhart et al. (2012) Citations: Chin, M., Ginoux, P., Kinne, S., Torres, O., Holben, B. N., Duncan, B. N., Martin, R. V., Logan, J. A., Higurashi, A., & Nakajima, T. (2002). Tropospheric Aerosol Optical Thickness from the GOCART Model and Comparisons with Satellite and Sun Photometer Measurements, Journal of the Atmospheric Sciences, 59(3), 461-483. Retrieved Dec 22, 2021, from https://journals.ametsoc.org/view/journals/atsc/59/3/1520-0469_2002_059_0461_taotft_2.0.co_2.xml Bond, T. C., G. Habib, and R. W. Bergstrom (2006), Limitations in the enhancement of visible light absorption due to mixing state, J. Geophys. Res., 111, D20211, doi:10.1029/2006JD007315. Engelhart, G. J., Hennigan, C. J., Miracolo, M. A., Robinson, A. L., and Pandis, S. N.: Cloud condensation nuclei activity of fresh primary and aged biomass burning aerosol, Atmos. Chem. Phys., 12, 7285–7293, https://doi.org/10.5194/acp-12-7285-2012, 2012. 2. Addition of OC and BC biomass burning aerosol emissions. These two aerosols are important during periods of active wildfires. Therefore, only when using a first guess aerosol source that has information about biomass burning emissions (e.g., GEOS-5), a user may include these effects through a new &physics namelist option: wif_fire_emit (logical). We note that if wif_fire_emit=.true. and wif_input_opt=1 (i.e., water- and ice-friendly aerosols only), then only OC biomass burning aerosols are emitted, as OC is included in the water-friendly category. However, if wif_fire_emit=.true. and wif_input_opt=2 (i.e., water- and ice-friendly plus BC aerosols), then both OC and BC biomass burning aerosols are emitted. This logic is handled using a surrogate integer variable (aer_fire_emit_opt) that is invisible to the user and thus defined on the Registry as a derived variable. Using the integer variable allows us to properly handle the new emission variables using packages while maintaining simplicity for the user to set a single, logical namelist option. To complement this enhancement, by default we distribute the OC/BC fire aerosols evenly throughout the PBL column (&physics namelist option: wif_fire_inj=1) as a simple plume rise parameterization. This is controllable through the namelist, and we set a warning message in check_a_mundo if the user is not running a PBL scheme with wif_fire_inj=1, as resolved vertical motions may be sufficient such that the parameterization should be turned off. 3. Modifications have been made to the METGRID.TBL file to handle the processing of the new QNBCA aerosol, as well as the surface emissions of anthropogenic QNBCA (QNBCA2D – similar to QNWFA2D and QNIFA2D) and surface emissions of OC and BC biomass burning aerosols (QNOCBB2D and QNBCBB2D, respectively). The modifications to METGRID.TBL may be found in the WPS#190 (wrf-model/WPS#190): We add entries to METGRID.TBL to handle the black carbon aerosol category in addition to biomass burning emissions. Specifically, we: * add monthly climatology entries for black carbon aerosol (B_WIF_*) which generate FLAG_QNBCA_CL for processing in real * add first guess entry for black carbon aerosol (QNBCA) which generates FLAG_QNBCA for processing in real * add first guess entry for anthropogenic emission of black carbon aerosol (QNBCA2D) which generates FLAG_QNBCA2D * add first guess entries for biomass burning emissions of organic carbon (QNOCBB2D) and black carbon (QNBCBB2D) which generate FLAG_QNOCBB2D and FLAG_QNBCBB2D, respectively Note that the new .dat file for monthly GOCART climatology is hosted on Google Drive: https://drive.google.com/file/d/1BYflyu65kP5giRYbTzKo6y4iSnTfb1Fw/view?usp=sharing 4. The ability to have time-varying aerosol emissions has been added. This capability is handled through &physics namelist option qna_update=1, similar to sst_update=1. The I/O for qna_update is done through auxinput17 and the file generated during real is called wrfqnainp_d0* (individual files for each domain, again similar to wrflowinp for sst_update=1). LIST OF MODIFIED FILES: M Registry/Registry.EM_COMMON M Registry/registry.new3d_wif M dyn_em/module_em.F M dyn_em/module_first_rk_step_part1.F M dyn_em/module_initialize_real.F M dyn_em/solve_em.F M dyn_em/start_em.F M main/real_em.F M phys/module_bl_mynn.F M phys/module_microphysics_driver.F M phys/module_mp_thompson.F M phys/module_pbl_driver.F M phys/module_physics_init.F M phys/module_radiation_driver.F M share/input_wrf.F M share/mediation_integrate.F M share/module_check_a_mundo.F M share/module_optional_input.F TESTS CONDUCTED: 1. We have conducted numerous simulations with the new code for a 21-day period in 2016 and a 9-day period in 2020 during active wildfire events. AOD/irradiance quantities from the model output have been compared to observations. For the 2020 wildfire event, our findings are summarized in a manuscript that is currently under review (Juliano, T. W., P. A. Jiménez, B. Kosović, T. Eidhammer, G. Thompson, J. Fast, L. Berg, A. Motley, and A. Polidori, 2021: Smoke from 2020 United States wildfires responsible for substantial solar energy forecast errors, in review at Environmental Research Letters). 2. Jenkins tests are all passing. RELEASE NOTE: A black carbon aerosol category has been added to the Thompson Aerosol-Aware microphysics scheme. Moreover, code enhancements are introduced to allow for time-varying surface aerosol emissions, in addition to consideration of biomass burning organic and black carbon aerosols when using a first guess aerosol source (e.g., GEOS-5).
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