Radiative Transfer - Science topic

Stam Nicolis I checked these references thoroughly. Actually, the document written by Duncan Forgan was the one I used to implement (probably) my first Radiative Monte Carlo code about 10 years ago. Still, I couldn't find what I was looking for. Maybe I am not making myself clear, but what I would like to know is if there is a document that clearly and explicitly explains the relation between the MCRT algorithm (i.e. steps involved and the iterative structure) and the Radiative Transfer Equation (e.g. the algorithm's relation to each of the operators present within the equation). I.e. a relation between MCRT and the RTE without resorting to the "imagine what happens to a photon in the physical scenario".

Thanks a lot for your suggestion. I will consult the text of van de Hulst.

Y.C. Zhong thank you so much for your valuable comments.

Why don't you design an experiment to measure the changes in those properties in the first place? Then you could build/choose a theoretical model.

When inverting the radiative transfer equation (Chandrasekhar radiative transfer equation, eq.(2.3) from Seidel(2011)) you do not need to perform the expansion of an exponent because you can obtain the analytical solution of he equation

(1-N)=exp(-\tau \eta)

Even in this case you will still need to satisfy the condition N<1.

Thank you, Ismail Mondal!

You can download the SBDART model zip file from this GitHub link:

Then simply in Unix environment you can proceed with SBDART installation using following commands:

unix> gunzip sbdart_2.4.tar.gz

unix> tar xvf sbdart_2.4.tar

unix> make

These documents are very helpful for SBDART installation and input parameters.

In the the Stefan-Boltzmann law , only one variable parameter is epsilon. This will come under heat exchange between surface. You need to feed the both the emissivity of surfaces which are considered.

Hello Tobias,

I had no idea how difficult your question was until I tried to answer it myself. I tried looking in two books on heat transfer that I normally use:

R. Byron Bird, Warren E. Stewart, Edwin N. Lightfoot; Transport Phenomena; John Wiley & Sons, Inc.; 1960; p. 432 (Table 14.2-1).

Frank P. Incropera, David P. De Witt; Fundamentals of Heat and Mass Transfer, 2nd Edition; John Wiley & Sons, Inc.; 1985; pp. 779-781 (Table A.11).

While the book by Bird, Stewart, and Lightfoot gave the total emissivity for a thick (?) film of water at 495 and 672 degrees Rankine (absolute temperature in degrees Fahrenheit), there were no citations to source literature, only the following rather unhelpful note: "Calculated from spectroscopic data." One can, of course, look at the absorption spectra in the IR (Infra-Red) as measured by a spectrophotometer in standard books on chemical structural analysis, but it is not clear how one goes from the limited spectrum in the IR to the total emissivity. The following book shows the limited IR spectrum for both H₂O and D₂O:

Daniel J. Pasto, Carl R. Johnson; Organic Structure Determination; Prentice-Hall, inc.; 1969; p. 356.

The book by Incropera and De Witt has a table listing the hemispherical emissivity for ice at 273 Kelvin and liquid water at 300 Kelvin. There is a note claiming that the data from the table came from four different reference books 1, 9, 24, & 25 (see pp. 783-784 for the citations). Unfortunately, I only have access to reference book #1, the 14 volume set of reference books by Y. S. Touloukian et al.; Thermophysical Properties of Matter; Plenum Press; circa 1970s . I have examined volumes 8 and 9, Thermal Radiative Properties, Nonmetallic Solids and Coatings, but there are no entries for ice or liquid water. The other three reference books are as follows:

#9, J. F. Mallory; Thermal Insulation; Van Nostrand Reinhold; 1969.

#24, G. G. Gubareff, J. E. Janssen, R. H. Torborg; Thermal radiation Properties Survey; Minneapolis-Honeywell Regulator Company; 1960.

#25, F. Kreith, J. F. Kreider; Principles of Solar Energy; Hemisphere Publishing Corp.; 1978.

Anyway, I really like your question.

Regards,

Tom Cuff

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

It depends very much on what you want to achieve. If, say, you were studying the radiative transfer (RT) through a layer (of clouds, aerosols) in an atmosphere where the profiles of temperature, humidity, and other radiatively active gases and the cloud and/or aerosol optical properties are not perfectly known/measured, over an area where the surface radiative properties are very variable (say, an ice and snow surface with liquid water ponds on top), one could either 1/ run N times the same RT code with a small change in one of the defining properties (with that small change consistent with the overall probability distribution of the variations for that property (PDF)) then look at how the results actually pan out (to figure, for example, what parameters are really dominant to define the result), or 2/ (more efficient) modify the original RT code to include (for the parameters one is interested in) some random number generators to be used to draw values from the PDFs of the relevant parameters.

Method 2 has been used for RT codes in GCMs in a series of publications by Howard Barker, Robert Pincus and collaborators (and some others) in the last 15 years. If your application is GCM-related, you might want to search for « McICA » (Monte-Carlo Independent Column Approximation).

Dear sir it means reemission in participating nanofluid in receiver with isothermal temperature below 750 K is always neglected?

Answer from Dr. Silas E. Gustafsson - Pioneers of Thermal Conductivity Measurement( silas.gustafsson@thermetrol.se): Silas E. Gustafsson

When comparisons are made between data obtained with the Hot Disc (HD) method and those of most other methods, it should be remembered that the transport properties measured with this method are the properties of the substrate beyond the surface, where the structure starts to repeat itself and assumes stable or bulk properties. The reason why it is possible to avoid the influence from the thermal contact resistance between the sensing spiral of the probe and the first surface representing the “bulk” properties of the substrate stems from the fact that the transient recording of the thermal transport properties of the substrate is normally much longer than the time it takes to establish a constant temperature difference across the thin layer comprising the probe insulation and the surface roughness of the substrate (cf Gustavsson, J. S., M. Gustavsson, and S. E. Gustafsson. (1998). On the Use of the Hot Disk Thermal Constants Analyser for Measuring the Thermal Conductivity of Thin Samples of Electrically Insulating Materials. Thermal Conductivity 24, Technomic Publ. Co. Inc., pp 116 -122.). In this paper we discussed how to separate the thermal contact resistance between the probe and the substrate from the transiently recorded data in this ITCC communication some 20 years ago. After this conference professor Cahill applied the suggested procedure for all the measurements he has made on very thin insulating layers with his 3-omega method. The reason why it is possible to separate the thermal contact resistance between the probe and the substrate surface from the measurements of the bulk of the substrate is the different time scales we are dealing with.

I recommend Frank's answer

Look this:

1 Watt /m2 = 0.0864 MJ /m2/day

1 MJ /m2/day  =0.408 mm /day

For a ETr of 0.2mm/h, LEcold in METRIC should be around ~ 143 W/m2 (1.05*0.2*681.6, where 681.6 is the scale factor to convert mm/h to W/m2). In SEBAL, LEcold is typically taken as Rn-G (i.e. H = 0).

This is a real interesting topic. Have you find a solution by chance?

Sundara, as far as I remember, night time Landsat 8 acquisitions are made by special requests only. USGS also makes already requested night time Landsat scenes available for download. But so far out of the 1 million plus scenes acquired with Landat 8 hardly 0.01 % are night time scenes. I imagine for thermal inertia and diurnal surface temperature studies, day and night lst pairs would be very useful but I don't know if we can expect night acquisitions regularly. ASTER is another alternative but I am not sure how many night time scenes are available for India. Are you looking for night time scenes for the entire country or specific area in India? In any case, try the special request option with USGS.

And what do you mean by, '(Land and water area must be there)' and 'that would not be having water and land areas together' in your question?

what are your inputs? What operating system do you use? If you manage to get (x,y) columns in ASCII format, you can use something like Origin under Windows or xmgrace under Linux.

I would also recommend to use the ASTER Spectral Library. From my own experience the spectra you can find in the mentioned library are in very good correlation to spectra of the same soils measured by Diffuse Reflectance Infrared Fourier Transform Spectroscopy. Therefore we used a Praying Mantis™ from Harrick in the MIR spectral region.

A great textbook describing calculation of the radiative transfer / absorption of various atmospheric gases in clear and scattering conditions is "Atmospheric Radiation: Theoretical Basis," by Goody and Yung. It should have the information you're looking for.

By improving the optical density in the vicinity of plasmonic nanoparticle by means of Surface Plasmon Polariton (SPP). SPP is the collective oscillation of the surface charges of the metal nanoparticle coupled with the electromagnetic wave for a specific frequency.... So,  increase in optical density may leads to the increased light-matter interaction and hence it improves the radiative transitions....

Regards

Sivan

It's probably not related to the platform (Linux), but there might be differences in Fortran compilers.

Unfortunately, the developer of SBDART has lost his job many years ago, so the code is not supported and should be considered antiquated.

Dear Derek,

I assume you know about ESA's recently approved Explorer mission 'FLEX', but if not, you'll find more information about it here:

Of course, a web search for "esa explorer fluorescence" will generate thousands of pages... Now, plant materials are quite different from an acrylic plastic sheet, but perhaps some of the physics may be relevant.

Good luck with your investigation. Cheers, Michel.

I have found an interesting paper regarding this topic

hi, as far as i know, normaly Mie-scattering is used for measuring liquid phase. if you want to measure the vapor phase, Schlieren technique is one of the options. I do not know why does Peter Frijters use so complicated setup to do the Mie-scattering. Usually we use  similar setup as IFPEN to measure the liquid length.  It does not matter you use the LED or laser or other kinds of lamps as the light source, as long as the intensity is strong enough 

It depends on the species and line you  want. 1-1000eV is  very large range. At 1000eV you probably have highly ionized  heavier Z species for which  natural broadenig which scales as Z**4 can be important. At 1 eV on the other hand  you probably do not have ion lines. I assume you imply LTE and hence Doppler, ion and  electron temperatures are more or less equal.  I believe if you are more specific on lines and species (e.g.  FeXV 3p2-3p3d) you can get more useful replies. Generally Voigt=Gaussian(Doppler) +Lorenzian(Stark&natural), neglecting any coupling which is usually small. As for fine structure in many cases if other broadening mechanisms like Stark and Doppler are significant, they will mask fine structure differences and you will see a big blob. But if they are not, then you might see fine structure too. I would check how large is the fine structure splitting and compare it to Stark and Doppler width. If eiher of them dominates fine structure, I would -at least to your level of approximation- neglect fine structure.

So I would  suggest you post the specific lines (you should know that because presumably you are looking at a given spectral range) to get more helpful answers 

P.S. Typically one does not use density, but electron density (e/cc) because only the ionized part perturbs the emitter and at 1 eV  you may not have that much ionization.

You can use Fluent. Here is a Thesis link for your help :

If you want to compute vertical profiles of shortwave and longwave radiative fluxes, you could have a look at rtweb.aer.com

There are a lot of information on various pieces of codes, and most of them can be downloaded for free after registration. The codes are in Fortran.

For publicly available three-dimensional radiative transfer codes check http://i3rc.gsfc.nasa.gov/Public_codes_3DRT.htm

Probably, there are many works related to your question in the JQSRT, some of them by M. Mischenko et al. (http://www.giss.nasa.gov/staff/mmishchenko/mishchenko.html). Also, the Amsterdam database is a database of the scattering matrices and optical properties of aerosol and hydrosol particles cited in several articles (http://www.iaa.es/scattering/amsterdam/index.html).

Try these:

Tsay, S. C., K. Stamnes and K. Jayaweera, 1990: Radiative transfer in planetary atmospheres: Development and verification of a unified model. J. Quant. Spectrosc. Radiat. Transfer, 43, 133–148.

Chenxi Wang, Ping Yang, Steven Platnick, Andrew K. Heidinger, Bryan A. Baum, Thomas Greenwald, Zhibo Zhang, and Robert E. Holz, 2013: Retrieval of Ice Cloud Properties from AIRS and MODIS Observations Based on a Fast High-Spectral-Resolution Radiative Transfer Model. J. Appl. Meteor. Climatol., 52, 710–726.

doi: http://dx.doi.org/10.1175/JAMC-D-12-020.1

Hanno, I understand your problem and I have never seen its clarification.  Here is my own version:

For any finite set of masses and springs, no matter how irregular, we can find its eigenfrequencies, right?  This is what is called phonons (usually).  But you probably expect some relation with reciprocal lattice?  Well, the reciprocal lattice is more or less the Fourier transform of primary lattice nodes.  Thus exactly the same qualitative picture may be obtained considering irregular set of atoms, just like it takes place in glasses.  The bad news is that when going to infinite glass we obtain not a discrete but continuous set of reciprocal lattice points (k-vectors).  As the distances between real atoms cannot be arbitrarily small, then such k-spectrum should be bounded, even in infinite glass.  Therefore we can talk about the maximum energy of mechanical vibrations in glasses ("phonons").  In this picture, however, there is no place (at least I can't see it) for microscopic polarization of such "phonons".

Dear JAvier,

Raman scattering will only impact your upwelling radiances (and then reflectance) in clear to relatively clear waters and from about 490 nm. Typically water with Chlorophyll concentration lower than 0.3 mg.m-3. It can affect the remote sensing reflectance up to 10% (perhaps 20% in very clear). Raman is an inelastic process (as fluorescence) due to the excitation of water molecules. Due to the relatively low sea water temperature "Raman photons" only appear at longer wavelengths compared to the excitation wavelength. It is therefore more and more visible at higher wavelengths. However, the increasing absorption of water molecules toward high wavelengths compensate this effect (Some Raman photons get absorb by water).

If you want more details you can read the book of C. Mobley: Light and water.

or/and the following papers:

Morel, A., Antoine, D. and B. Gentili (2002). Bidirectional reflectance of oceanic waters: Accounting for Raman emission and varying particle phase function, Appied Optics, 41, 6289-6306

hope it helps

best

hubert

I have made this kind of calculation (a paper is available on my account) with my own code. I have no experience of calculation with commercial codes.

What makes you feel that the heat transfer may really not matter in the varied agricultural applications mentioned?

Hi Lambert,

Yes indeed you are the first one to tackle this question. I must be honest, it is a question of which we do not know the answer yet. Be we have defined a research project in a remote sensing programme in my country, under which it should be possible, looking at different angles from an aircraft to a tree canopy to determine the measuring conditions under which it would be possible to make a distinction between the abaxial and adaxial sides of a a leaf.

Why would we like to know that yo ask ? Well with ground level leaf reflectance measurements we could already demonstrate that the ratio of abaxial to adaxial leaf reflectance is dependent on the impact of pollutants (fine dust, NOx, SO2 and soil pollution, and maybe other ones as well). Hence it is a nice biomonitoring approach in cities. For example in a street with lots of traffic this ratio changes as opposed to a street with only a small or insignificant traffic flux. We were able to demonstrate this in two cities in Europe, Gent and Valencia, hence a city in a Western European climate and one in a Mediterrranean climate. They both gave very positive results. Hence when we would be able to determine the measuring conditions at canopy level under which the difference between the reflectance of (mainly) the adaxial side, or (mainly) the abaxial side can be measured, we would able to map the impact of pollution (as a mytter of fact the integrated pollution impact on trees) in a lot more cities.

That might be pretty interesting from the epidemiological view as well, because we are also talking about the impact of fine dust on trees here as well.

So that's why I asked that question here above, which is a complicated one indeed. There is effectively the wind field which can play a role, but which can be avoided, by looking carefully at the meteo conditions during flights. Most importantly we think that the angular distribution of leaves on a tree plays a fundamental role in this venture. So the first focus will be on simulating trees with different leaf angle distributions (LAD's) and then check under which angles of view and azimuth ;-) we can detect a majority of adaxial versus abaxial sides of leaves and vice versa. There will evidently be a mix of both sides of the leaves being visible, but the trick is to find the conditions where these sides can be viewed in their most seggregated mode. And maybe some unmixing algoithm might help us to unmix the abaxial form the adaxial reflectances as well.

If we would succeed in separating abaxial form adaxial leaf sides at the canopy level, for certain frequently occuring tree species in a city, then we are in business for the biomonitoring of air and soil pollution in cities ising tree canopies.

I figger that might give the hot spots of air pollution as well as soil pollution in urban environments. With an airborne campaign of maybe three flights ( or 3 days) it would (might) be possible to completely map a city like Gent or Valencia (middle sized European cities) integrated pollution levels, and pinpoint the hot spots, to be able to study these more in detail and try to remediate, the high pollution levels whic sometimes are street canyons with lots of traffic as we saw in Valencia.

I hope we can shift the funding our way, to be able to perform this work

By the cay thanks Lambert for showing interest in the topic. It might be interesting in cancer research as well when we would overlay let's say a cancer incidence map with an integrated pollution map for a certain city in the Benelux. You never know what that would give. Maybe fireworks. Just imagine.

Cheers,

Frank