Radiative Forcing - Science topic

Dear ResearchGaters

Many thanks for helpful answers in the past. If you have time, please can you look at the following table taken from

https://energyeducation.ca/encyclopedia/Radiative forcing.

Radiative Forcing in CE 1750 was taken to be 0 W/m2

“ “ 1950 “ 0.57 = W/m2

“ “ 1980 “ 1.25 = W/m2

“ “ 2011 “ 2.29 = W/m2

What I would like to clarify is, what are the working figures – how many watts, what is the area? is it the surface area of the Earth?

Any help would be gratefully received!

Methane (CH₄) is nearly 86 times stronger as a greenhouse gas than carbon dioxide (CO₂) (Dean, 2020). Scientists believe roughly one-fifth of the increase in radiative forcing by human-linked greenhouse gases since 1750 is due to CH₄ (Nisbet et. al., 2014, Javadinejad et. al, 2019).

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You may have a look on my thesis to know more about the impact of methane on our environment.

Since indirect and semi-direct effect are related with perturbation in clouds, is it not better to use all-sky radiation(with clouds) instead of clear-sky radiation (without clouds)?

Many observations and calculations of the atmospheric absorption can be found, but it would appear very few studies on climate had explicitly applied the basic radiative transfer equation in different forms, including scattering and atmospheric radiation. If you know any relevent references or your own papers to share, that would be wonderful.

I am calculating the radiative forcing of Black carbon using SBDART, I need satellite AOD to compare AOD from OPAC but there is no MODIS data for 3 months (Jul. to Sep. 2019) and no AERONET data. How can I compare AOD?

I'm looking for the matlab code of 6SV model to calculate the Dust, Biomass-Burning, and Anthropogenic radiative forcing. If there anyone who have, please send me a copy. Thank you very much.

I am looking for SBDART model , either online or offline. The online model I found

doesn't seem to work , and the MATLAB code i got from here shows error. Any other source for the model ?

I am interested in looking at the radiative forcing due to BC, I have daily BC concentrations and mass concentrations of water soluble and insoluble elements. I have chosen atmospheric profile as tropical, surface albedo as vegetation and boundary layer aerosols as rural. But when I try to give two profiles for boundary layer aerosols as rural and tropical then I end up with error "can not match namelist object".I am also confused in how to feed OPAC generated values in SBDART.

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.

Dear All,

I'm working on the projections of Global mean temperature change (observed data obtained from NOAA, 1959-2018) based on green house gas emissions.

For this, I have tested several regression equations but not exactly able to compare these forecasts with IPCC report (TAR and or SR15).

I want to know is there any equation which mathematically or statistically explains these changes in global mean temperature based on CO2 concentrations or CO2 equivalent concentrations in PPM.

In the Radiative Forcing terms, one known reationship is,

delta(t) = Lamdba*delta(F).

where, delta(F) = Radiative forcing = 5.35*log(C(t)/C(0)), where C(0) = 278 PPM (CO2 concentrations in yr 1750).

But issues is that when we plot the calculated temperature change using this equation with observed NOAA data of temperature change, they aren't same. The observed curve is more steep than calculated one.

One more challenge could be the value of Lambda, some are saying that this value is 0.5 or 0.4, but even both values aren't leading to correct curve of temperature change.

What are your thoughts??

Best Regards,

Abhay

I am working on a project on Radiative Forcing due to Black Carbon. The aethelometer data is Mass Concentration but the input needed for OPAC is number density. Is there default conversion value or any other method for this purpose ?

In practice, how is BC GWP estimated from radiative forcing monthly values?

Hi,

As morphology of the aerosols also play roles in deciding its optical properties & radiative forcing, Is any morphological studies going on under this project?

Aerosol, Black carbon, OPAC, SBDART, AOD, Radiative transfer model

I have estimated monthly BC radiative forcing at a particular location. Now I wanted to estimate the global warming potential using the radiative forcing values. Can anyone explain what the global warming potential refers to and how can I compute the same? 

I am getting relatively lower downward diffuse flux when I increase the ozone concentration in lower atmosphere at around 40 degree of solar zenith angle. Can we define this effects in terms of multiple scattering ? How?

Hello everyone,

I just started to work with SBDART Radiative Transfer Code. I have downloaded the source files (FORTRAN) on my LINUX machine and compiled it. After that I ran the model for a given INPUT (from examples file).However, results generated from my run are different from those given in example output (for same INPUT). Could anybody explain why I am getting different results? Does SBDART calculation depends on machine?

I got nearly identical images when plotted both fields.  Can anyone explain?

Supposing that I have mass concentration profile data of different aerosol species (dry state) along with RH profile from a chemical transport model (CTM). This CTM do have an internal aerosol routine which calculated AOD & SSA. In order to compute aerosol radiative forcing (ARF), one required scatter phase function or asymmetry parameter in addition to AOD & SSA values. Of course, I am aware that atmospheric profile data & surface reflectance information are also needed, which can be obtained respectively from radiosondes (alternately use climatological atmospheric profile that corresponds to the region of study) and MODIS. As per the above description of available data, I chose to use OPAC (assumption of external mixing) to compute the aerosol optical and scattering properties by using mass concentration data of different species. Once I have AOD, SSA and g, I was using the SBDART to compute ARF. 

My main questions are:

(a) Are there studies focused on giving a detailed uncertainty estimate combining all sources of uncertainty from measurements/model simulations till radiative forcing computation (say using offline RT model)?

(b) Is there any study which give the uncertainty in ARF computation by using asymmetry parameter instead of scattering phase function?

(c) What is the uncertainty of a general chemical transport model simulations of aerosol species mass concentrations? 

Dear all. There is a queatsion about aerosol bothered me. In the CAM4.0 and the previous version of CAM, the aerosols are prescribed, meaning that the model doesn't include the interaction between aerosol and cloud, and the aerosol chemsitry. IPCC AR5 reported that the radiative focing of the aerosol-cloud interactions is larger than the radiative forcing of aersol-radiative interactions. So, in the CAM4.0 and the previous version of CAM, whether the radiative forcing of aerosols will be underestimated? And in this situation, how does the the model represent the climate change well?

Is there any method available for the estimation of cloud albedo using satellite observation of shortwave and long wave radiation at TOA for clear and all sky? 

How can we calculate cloud albedo?

It does not matter if the data is a total net forcing or in each individual part.

In my case, I don't think OPAC and SBDART serve my purpose!

I want to estimate aerosol direct radiative forcing on IGP region.

Please suggest some dataset and methods for estimation.

Climate sensitivity is the equilibrium temperature change in response to changes of the radiative forcing. Therefore climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise palaeoclimate data. Slow climate feedbacks, especially changes of ice sheet size and atmospheric CO2, amplify the total Earth system sensitivity by an amount that depends on the time scale considered. (wikipedia)

Or will anything below 50-60% will do? After all, a majority of particles are in liquid state in this type of environment.

I try to measure radiative forcing in northwestern Argentina using a NIP and PSP.