Tropical Meteorology - Science topic

Check this link: https://www.ecmwf.int/

As I know there is no historical ranking because (1) MJO discovered in 70s (2) still there is no universal accepted theory of MJO (3) reproduction of MJO by most GCM models is not doable.

CORDEX outputs is at 50km spatial resolution (0.44degrees)

Dear Prabhat chandra Neupane,

See Figures 7.7 and 7.8 (Chapter 7: Scale of the Atmospheric Circulations) in the book below.

Regards,

Milivoj B. Gavrilov

Please be concentrated towards remote sensing data for precipitation measurement in a mountain belt latitudinal and longitudinal to reach the conclusion.

The atmospheric Hadley cells are the most stable part of the circulation system; at the surface they are the trade winds. They extend from ca. 5 to 25 N and S. You can make maps showing the plate tectonic evolution of the Caribbean at www.odsn.de/odsn/services/paleomap/paleomap.html

The paper with the plate tectonic details is Hay & Wold 1996 on my Researchgate site. Cretaceous climate model simulations sometimes produce 'supercanes'. Our first modern ones happened in 2005: see

Bill Hay

Hi Cazorla,

You have mentioned that your domain is  over the equatorial Andes in South America, which has  very complex topographic distribution. I do not know how big is your domain and at what resolution you are planning to run WRF and how many nest? 

WRF model's physical parameterization depends on the all the above above factors. If you look at available literature on WRF models sensitivity analysis then you will see that nearly all study concluded their papers as saying that do not choose physical parameterization combinations based on other study as WRF results depends on season, study location, variables of interest, domain size, length of simulation.

In my PhD research, I have done a comprehensive sensitivity analysis of WRF model over Canada and find that WRF results are sensitive to the above listed factors. 

Nevertheless, you will not find any other places which has steep mountain (Andes) and very cold ocean (East pacific). So, I would suggest you to do a small ensemble sensitivity experiment over your domain if you have computing resources and time.

Last but not least, I would strongly suggest you not to follow blindly other peoples selections. 

I hope that helps.

Thanks

Hi Muhammad, 

The appropriate representation of  "El Nino" is ENSO (El Nino Southern Oscillation). The "El Nino" only represents the Oceanic component and the Southern Oscillation indicates the Atmospheric component. Hence the name ENSO. In the atmospheric science community people use multiple indexes to define ENSO. The El Nino is defined as an increase of Eastern Tropical Pacific's sea surface temperature (SST) of 0.5 degree C from long term average (normally 30 years). And the La Nina is defined as a decrease of SST over the same area by -0.5 degree C from long term average.        

The ENSO has a recurrence interval of 2 to 7 years. You can use multiple tools to compute the return period or recurrence interval. I had used the Wavelet analysis tool to calculate amplitude and frequency of ENSO event in one of my graduate level course project.   

Beside the above link that Dr. Kenneth given, I would like to suggest you to visit the following web link for a series of articles on ENSO including different ENSO indexes; role of ENSO to global weather and climate  by renown atmospheric scientist professor Anthony G. Barnston's of Columbia University.  

Multivariate ENSO Index (MEI)

http://www.esrl.noaa.gov/psd/enso/mei/ 

Why are there so many ENSO indexes, instead of just one?

https://www.climate.gov/news-features/blogs/enso/why-are-there-so-many-enso-indexes-instead-just-one 

https://www.climate.gov/author/anthony-barnston  

Hope the above link will help you to find your answer more broadly 

Thanks Leonardo!

I'm just collecting basic climate data for a interpretation of some literature data. I recieved the climate data already (via worldclim). My question focuses on the interpretation of the data. 

I need a simple parameter to express the seasonality of precipitation to devide the literature sites into semi-humid and humid tropical. The Coefficient of Variation of the monthly rainfall (over several years) seams to be a possible way to express seasonality in my opinion. But from which CV on a site is called semi-humid?

Let's talk about the SC-parameterization soon. I trying to get access to a really nice dataset of SC-field data here from Goiania. I will get back to you when I get it.

Best wishes,

Dennis

The general thinking is that the ITCZ / Hadley circulation shifts toward the warmer hemisphere; this is in line with the seasonal variation as noted in Vadym's answer. A number of recent studies have shown evidence that extratropical heating anomalies have an impact on the tropical precipitation, particularly by affecting the position of the ITCZ. Examples:

Hwang, Y.-T., Frierson, D. M. W. and S. M. Kang. Anthropogenic sulfate aerosol and the southward shift of tropical precipitation in the 20th century. Geophys. Res. Lett., 40, 1-6, doi: 10.1002/grl50502, 2013.

Ceppi, P., Hwang, Y.-T., Liu, X., Frierson, D. M. W. and D. L. Hartmann. The relationship between the ITCZ and the Southern Hemisphere eddy-driven jet. J. Geophys. Res.-Atmospheres, 118, 5136-5146, doi: 10.1002/jgrd.50461, 2013.

What becomes apparent as you dive into this topic is that it isn't really the details of the energy source that matter. That is to say, it isn't the ice that matters in your example, or the sulfate aerosol in Hwang et al. Instead is the impact on the global energy cycle. 

Realizing that it is the global energy cycle that matters in these issues then brings the whole thing back to trying to understand fundamental aspects of the circulation. On this topic, there are a few recent studies that have noted that the impact on tropical precipitation of these high-latitude effects may depend on the representation of the ocean. In particular, a number of studies that show these tropical effects from extratropical forcing use only a thermodynamic ocean. Sometimes introducing a fully dynamic ocean model allows the oceanic response to adjust cooperatively with the atmosphere, and the tropical impact is substantially reduced. Two examples that show this pretty explicitly are:

Tomas, R. A, C. Deser and L. Sun, 2015: The role of ocean heat transport in the global climate response to projected Arctic sea ice loss. J. Climate, submitted. [preprint from Clara's web page: http://www.cgd.ucar.edu/staff/cdeser/docs/submitted.tomas.ocean_heat_transport_arctic.sep15.pdf]

Kay, J. E., Yettella, V., Medeiros, B. Hannay, C., and P. Caldwell (revised), Global climate impacts of fixing the Southern Ocean shortwave radiation bias in the Community Earth System Model, J. Climate, [preprint from Jen's web page: http://www.cgd.ucar.edu/staff/jenkay/papers/Kay_JClim_SouthernOceanASR_revised_November2,2015.pdf]

Hope that is helpful.

Hi Thomas,

I am not sure if you already have a satisfactory answer, but I would like to provide an answer anyway. First of all, I am glad to see that researchers/engineers across the world are still on a look out for a robust method to identify stationarity in wind speed time series. It gives me some comfort that I am not alone in this. 

After parsing through the literature in the past, one of the better methods that I could think of is from Andreas et.al. (2008). It somehow takes care of correlations on a very short time scale, which I believe they do by estimating the integral time scale. Please find the details in this publication.

In case you have found a new/better method then I am very interested to know that too. 

Kind Regards,

Ameya

one year ago , I found it , and downlaod from the official weasite. But I don't know why they disaperar recently, if you want , I would forward the data which I download one year ago.

 In science, if we want to investigate any scientific problem, major influence factors should be given more priority to be investigated. However, only one field is an exception: that is global climate warming. Many scientists ignore the major climate influence factors and consider greenhouse effect  due to human reasons to be the main reason , although they knew it is much smaller than the major climate factors.

     Their logic is that the recent unusual trend of land surface temperature is non-periodic, major periodic factors only cause periodic changes.

     Recently, after more than a half year's effort, we prove that the monthly anomaly of global land surface temperature can be fitted perfectly by a group of periodic functions, the verification results indicate that the correlated coefficients of more than 15,000 periodic functions are all more than 0.9.(Last year, I mentioned I found a function which its the correlated coefficient is 0.8)

    I send the paper to one of the toppest IF magazines, the editor said" we know  your reseach result is absolutely right,but many people already believe in this view, thousands of papers have already published , so we have to reject your paper. And we also tell you that  no magazine is willing to publish your paper".

    One anonymous email is send to me with the following word :

         "Birth is much, but breeding is more."

In Mexico you would have to log into the National Meteorological Service web page and choose de automatic weather station option. Most of this stations measure every 10 min and report measurements either every hour or every 3 hours. You would have de choice of data for last 24 h @ 10 min, or last 7 days @ 60 min or last 90 days @ 24 h.

You could ask Frank Wadsworth and John Parrotta in the US Forest Service, both of whom were familiar with Holdridge and his original classification. - JB

I have to respectfully disagree with Alastair McDonald's reply.  The upper air away from the surface does of course follow the cylindrical circulation (so long as you are still low in the atmosphere).  But the question is about wind close to the surface, which is governed not only by the pressure gradient and coriolis effects of the upper air, but also frictional effects from the surface.

The Eckman calculation is single column, and is indifferent to the large scale circulation.  In a low pressure system you see the effects as air near the ground cuts across the pressure contours at nearly 45 degrees, but upper air follows the pressure contours.  A hurricane is just a massive low pressure system.  The Eckman profile holds at each location, so that the wind near the ground inclines towards the local low pressure (not directly towards it) while higher  air will circulate perpendicular to the pressure.  Higher still the wind becomes vertical, then eventually switches to circulating the opposite direction.  But all this higher stuff is not Eckman circulation, and does not pertain to the question about surface winds.  About a km high the air is moving around the local low pressure; below it begins to turn so that near the ground it has a component towards the low pressure.

Over ocean, the friction is low ccmpared to land, so near the surface the wind will be closer to circulating around the low pressure than over land, but will still have a component towards the low pressure.

In my knowledge TRMM do not provide hourly data. The maximum temporal resolution is 3 hourly for trmm but there are some other RS data like CMORPH (ftp://ftp.cpc.ncep.noaa.gov/precip/CMORPH_V1.0/RAW/) which also has 30 minutes temporal resolution but the spatial resolution is coarser (2.5deg) and I think this data is not recommended for tropical region.

the ftp link to download netcdf files of TRMM data is (3 hourly, daily and monthly mean)

the other link to download TRMM data is (Here you can download the TRMM data in other file formats also)

http://mirador.gsfc.nasa.gov/cgi-bin/mirador/presentNavigation.pl?tree=project&project=TRMM&dataGroup=Gridded&CGISESSID=67f76647fcc7e698a94c7fa484fd3556.

I hope this gives you the answer.

Dear Wancan

I do agree with Fabrice Lambert response. The seasonal ITCZ shift is a regional process. It is associated with the seasonal differential warming between the continent and the ocean. The problem you pose is interesting in case of global warming, as both continental and oceanic warmings may exist. So the question is how this differential Continent/ocean warming may evolve. I have not the solution but you may find some consideration on the coupling between the ocean and atmospheric monsoon in a peper I recently published with csome considerations of the variability of the coupling. You can find the paper on my reaserch gate site.

Regards

The book:

Solar Engineering of Thermal Processes, 4th Edition

Gives a lot of information specially in appendix for solar simulation. There are many formula for sun directions and so on.

Pseudomonas type of bacteria species  is a common ice nuclei (IN) positive bacteria found among many other bacteria in clouds. There are several findnings on Pseudomonas syringae over the globe.  In India, we have collected Pseudomonas aeruginosa from Northern part of India and tested the ice nucleating characteristics of this particular bacteria over Indian subcontinent.

Bio-aerosol like bacteria can be nucleated at higher temperature and lower super saturation value that may helps to initiate cloud glaciations more quickly in terms of precipitation.

see "Study of ice nucleating characteristics of Pseudomonas aeruginosa” A. Hazra, M. Saha, U. K. De, J. Mukherjee and K. Goswami,; Journal of Aerosols Science, vol, 35, pp 1405-1414, 2004."

see "“Parameterizing ice nucleation rates using Contact Angle and Activation Energy Derived from Laboratory Data” by J-P Chen  A. Hazra, Z. Levin, Atmospheric Chemistry and Physics, 8, 7431-7449, 2008."

see "“A classical-theory-based parameterization of heterogeneous ice nucleation by mineral dust, soot and biological particles in a global climate model”, Hoose, C.,J. E. Kristjánsson, J.-P. Chen and A. Hazra (2010): Journal of Atmospheric Sciences, 67, 2483-2503."