# Data source of the planetary boundary layer (PBL)

PBL is one key physical quantities aimed at analysing the condition of air pollution in an area of interest.
From WRF simulation, I can get the variable PBLH whixh represents the PBL height.
But, is there any free data source offering the observing PBL height all over the World?

For now, I can get the weather data from the NOAA weather center. The data based on observations at airports doesn't conclude the quantitative information of PBL.

Any recommendation would be appreciate!

• isnt PBL height the height of 850 hPa ? – gansub Apr 2 '16 at 7:43
• @gansub.Thanks for your reply. In WRF, there was a variable represent the height of PBL. Sometimes, I was thinking to analysis the trends of inversion zone in an area of interest based on the reality data. But I could find any useful data source to get the information about PBL or height of 850 hPa now. Could you have some recommendation? – Han Zhengzu Apr 4 '16 at 3:24
• across the world maybe difficult. But if your Government's satellite track the 850 hPa heights on a daily basis you could get this information. – gansub Apr 4 '16 at 6:20
• @HanZhengzu - arl.noaa.gov/documents/JournalPDFs/… . "Global climatology of PBL heights has not been compiled". Check the references in that link for aerosol specific inputs – gansub Apr 6 '16 at 7:47
• @HanZhengzu - that is understandable. There is no one single definition of the PBL height. Tropics and mid latitude would vary. Take a look at this post - researchgate.net/post/… – gansub Apr 6 '16 at 10:36

Not exactly. The PBL is a quantity more or less derived. you may be able to derive it from upper air observations, but a direct observation of it is not yet available. Here are some methods: https://e-reports-ext.llnl.gov/pdf/235179.pdf

The question you are asking is the equivalent of "Can we observe the Jet stream?" We cannot observe the jet stream, but we can observe the winds, from which we infer the jet stream.

The PBL depth is not easy to observe. It is the layer where the atmosphere is turbulent due to friction at the surface and convection. During daytime this leads to well-mixed potential temperature and specific humidity profiles and you can estimate where the well-mixed area ends. This, however, is complex, because you need accurate measurements of that. Even in radio-soundings it is hard to find the top of the PBL.

With more advanced equipment, as a ceilometer, you can use backscatter profiles, but these are more local measurements.

In short, a world wide set does not exist and probably (re)analysis data is the best you can get.

An interesting analysis can be found here:

http://kiwi.atmos.colostate.edu/pubs/Ahlgrimm-Randall.2006.pdf