I've calculated Direct Aerosol Radiative Forcing(DARF) values (W/m2) for Ahmedabad and Gandhinagar City, Gujarat, India using SBDART Model (AOD values as an input) at Top Of Atmosphere (TOA), Surface (Surf) and net Atmospheric Radiative Forcing(Atm).
Please let me know how to interpret these values and how to further analyse the data.
Hi... Yash
Aerosol Direct Radiative Forcing (ADRF) depicts the scattering and absorption of solar radiation by aerosols. the positive values of ADRF indicate the warming and negative values indicate the cooling.
I hope that you have calculated ADRF using up and down radiative flux values. SBDART only provides up and down radiative fluxes later you have to calculate radiative forcing using those values. This method is already published by the many aerosol experts. You can refer to those publications.
Estimated TOA and SFC ADRF indicated the change in flux at TOA and SFC by aerosols. ADRF in the ATM indicates the change in flux within the atmosphere.
Further, you can more clearly associate these estimated radiative forcing to the climate by calculating heating rate. heating rate depicts the warming of the atmosphere. This can easily associate with regional or global climate change.
Herewith I have given you a very basic idea, but I will suggest you to read the related publication and their interpretation. This will give you more idea.
Hope this will help. Feel free to ask me, if you have anything
Another interesting parameter that you can calculate is the Aerosol Forcing Efficiency (AFE) if you have also some measurements of Aerosol Optical Depth.
In fact, the aerosol direct radiative effect can be quantified by both the Direct Radiative Forcing (DRF) and the Aerosol Forcing Efficiency (AFE). The DRF results
strictly related to the radiative properties and concentration of the aerosol
particles, while the AFE is mainly dependent on the particle composition
and size. The SW- and LW-DRFs by aerosol are generally of opposite sign. In fact, aerosols cause the decrease of the incoming SW radiation at the surface due to their scattering and absorption properties inducing a cooling effect and a negative value of SW-DRF. Conversely, the absorption and scattering of atmospheric particles in the LW-domain enhance the greenhouse effect by trapping the outgoing terrestrial radiation and therefore the LW-DRF is positive at the surface. The magnitude and the sign of the aerosol DRF are also dependent on other parameters such as the particle refractive index, the altitude of the dust layer, the single-scattering albedo, the asymmetry parameter, and the surface albedo. The aerosol DRF affects the atmospheric dynamics by changing the thermal vertical profile and the atmospheric stability. Another parameter that you can estimate is the heating rate profile.
Salvatore
The aerosol forcing effect is defined for the EXTRA manmade aerosol
Thus knowledge on the composition and sources of the components is necessary, not only the AOD
2. The LW occurs for coarse aerosol thus dust-like particles and here the same is an issue how much of the aerosol is manmade versus natural "dust" desert sand / seasalt
No
Simply said the definition of DARF is the portion of the AOD exerted by manmade aerosol; see for instance
section 6.8 The Direct Radiative Forcing of Tropospheric Aerosols
in CHAPTER 6 Radiative Forcing of Climate Change
https://www.ipcc.ch/site/assets/uploads/2018/03/TAR-06.pdf
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