• Mahmoud Safar added an answer:
    Which one is correct: weather variables or weather parameters?

    Which one is correct: weather variables or weather parameters?

    For example: Air temperature is a weather variable or weather parameter? 

    Air Temperature: A measure of the average kinetic energy of air molecules at 2 meters (~6 feet) above the surface.


    Mahmoud Safar

    when you are working with  direct observation of atmosphere like temp., wind direction and so on, you are working with weather parameters but variables are output of numerical modeling output like pv or vorticity or rh that does not pick up directly from atmosphere.

    in data assimilation you must convert weather parameter to weather variable with retrieval equations

  • Watheq J. Al-Mudhafar added an answer:
    Is there any simple and reliable way to estimate missing climatological data ?

    I need to fill gaps in my daily temperature dataset (2008-2014). The temperature dataset were provided by hobos (in an arctic environment).

    Any advice in bibliography ?

    Watheq J. Al-Mudhafar


    I would use the methods included in the attached paper for missing data imputation.

    It is so easy to implement them in R.

    I can guide you about that if you prefer to use R.

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: The missing data problem in petrophysical properties especially core measurements of permeability is a crucial step in reservoir characterization. It affects the multivariate statistical inference of these measurements leading to non-efficient prediction and less accurate geospatial modeling. Consequently, many imputation algorithms have been presented in this paper to comparatively predict the missing values of horizontal and vertical core permeability for a well in sandstone reservoir in a southern Iraqi oil field. The algorithms are Mean Substitution (MS), Iterative robust model-based imputation (IRMI), Multiple Imputation of Incomplete Multivariate Data (MIIMD), and Random Imputation of Missing Data (RIMD). These algorithms have been applied based on the deductive statistical inference to impute the incomplete data. All the algorithms above have been illustrated and the predictions have been depicted for the data before and after the imputation process for all the algorithms with respect to the histograms and the vertical data distribution given the well depth. The results have shown that the Random Imputation of Missing Data is the best algorithm because the histogram has preserved its shape before and after the imputation. Therefore, it is the best one for accurate imputation of incomplete petrophysical data.
      Full-text · Conference Paper · Dec 2014
  • Atiqa Khan added an answer:
    How to calculate EVI from landsat 7 surface reflectance products?

    I have downloaded Landsat 7 surface reflectance products, How to use that in the calculation of EVI? and What should be the range of values in output

    Atiqa Khan

    @ Cole, by scale factor, what you actually mean? Kindly explain a little bit.

  • Kenneth M Towe added an answer:
    What is the origin of Atlantic Multidecadal Oscillation (AMO)?

    I am interested in the theories and evidence linking the AMO to Atlantic Meridional Overturning Circulation, solar forcing and possibly other causes in explaining this phenomenon.  Is there literature reviewing these mechanisms? Do you have links to relevant net sources.

  • Suman Kumar Kundu added an answer:
    Will anyone help me in interpreting the result of mann-kendall test statistics and sen's slope estimator?

    Precipitation data of 31 years has been entered in MAKESENS excel template to obtain the result.

    Suman Kumar Kundu

    Does MAKESENS - excel template provide modified mann kendall test for autocorrelated data?

  • Jane R Foster added an answer:
    Does any university organize international courses or summer schools on palaeoclimatology in this coming year 2016?

    I am looking for information on advanced courses in English that would be open for graduate or post-graduate level foreign students. This would be interesting for students specializing on climate reconstruction, past climate dynamics, current issues of climatology, and so on. Is there any web-sites listing such activities? 

    Jane R Foster

    I saw this tweet today: TRACE2016: Tree Rings in Archaeology, Climatology and Ecology. Białowieża (Poland) 11-15 May 2016 

  • Mohsen Ghanea added an answer:
    Which satellites are used to estimate the wind speed at the ground level?

    Satellites to measure sea surface wind speed can take different data, But for the monitoring of land surface wind speeds.

    Mohsen Ghanea

    You can used wind speed product with 1-3 km spatial resolution acquired by NCEP. To gain more information, you can refer to the following publication: 

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: Validation of satellite derived sea surface temperature (SST) is necessary since satellite minus buoy SST (= bias) relies on atmospheric and oceanographic conditions and time periods. This research validates MODIS (Terra and Aqua) satellite daytime SST with buoy SST at the northern Persian Gulf. Sixteen dates during June 2011 to June 2015 were selected for validation. The buoy-satellite matchups were gained within one image pixel (1 km at nadir) and ±6 hours in time. For most matchups, time interval was ±3 hours. Effects of total column water vapor, aerosol optical depth, wind speed, glint, and satellite zenith angle on bias are then investigated. These parameters are classified based on root mean square (RMS) difference between satellite and buoy SST. Final results represent a near-perfect R2 (>0.989) for both satellites. The bias was 0.07±0.53°C and -0.06±0.44°C for MODIS-Aqua and –Terra, respectively.
      Full-text · Article · Nov 2015 · Advances in Space Research
  • Mark D Powell added an answer:
    How can I combine the strong wind measurements from the manually operated Weather Stations with those from Automatic WS into one homogeneous series?

    Hi, we have collected the long time series of the strong winds from the manually operated stations for the past. For the last 10-20 years, we deal with AWS only at the same (or close) locations. We want to combine both type of records into a homogeneous series for each location. What are the best methods of adjustment for the strong winds? (Meaning daily maximum wind speed, neither mean nor monthly)

    Mark D Powell

    In addition to the great advice given by Enda (hello Enda!) you could also use standardization methods to convert the measurements to a standard terrain for comparison purposes.  To do that you would need longer term averages (at least 10 min) and would need to have an estimate of the upstream fetch roughness for each site as a function of wind direction (using G earth these can be qualitatively estimated or you can use gust factors from a long data set).  Assuming neutral stability (a good estimate in strong winds) you could then use some conversion methods to go from one roughness to another.  One method is to  use a profile eqn. and your roughness estimate to go to the top of the PBL, and then go back down using the standard roughness you want to use (e.g. open terrain).  Vickery et al have a paper discussing this that was in J. Climate and Applied Meteorology.  Good Luck!

  • Kenneth M Towe added an answer:
    What are the critical data and modeling limitations of current green house gas research?

    When you read scientific research related to climate change it is apparent that many types of disparate data are integrated when simulations of the future are made.  How does the educated, social scientist (with no climatology training ) evaluate the quality of the research and how it is integrated to produce different scenarios with broader or more narrow ranges of values?  Are many researchers focusing on the replication of research?  

    How would you rate the state of climate research:  nascent, developing, developed in specific areas, mature?  What are the biggests current gaps in our knowledge of ocean and atmospheric systems...?  Are there also gaps in modeling the interactions between systems that contribute to less certainty?   Does the climate change community readily admit to those gaps?  What are some significant recent anomalies?  Have they been accounted for sufficiently?

    How do you judge climate scientists that have gradually evolved into advocates?  

  • C.J. Stigter added an answer:
    Are there any papers on Climate Resilient Mapping?


    We have been working to evaluate which of the available farming system is more climate resilient among the available systems. Can you suggest some of the papers that are related to resiliency measurement? I found Climate Resilient Index quite interesting----any suggestion on it?

    Also, I could not find papers on it. please suggest!

    C.J. Stigter

    Why it is so difficult to find what you are searching for follows from the below, where one local mapping approach is discussed:

  • Ramiro Checa-Garcia added an answer:
    What is the suitability of NWP model in East Africa?

    I'm customizing WRF for operational prediction in East Africa. A recent suggestion is to compare with other models possibly UK's unified model, COSMO and AROME with WRF. Is this suggestion appropriate for a Ph.D study?

    Ramiro Checa-Garcia


    I agree that for a typical PhD a single optimal configuration of an operational prediction system should be enough. Probably you can identify those aspects of operational prediction that might be most relevant on your area/region and focus on systematically identify the best settings and parameterizations within the model. 

    My experience is more related with COSMO model than WRF. As WRF, it is also a free code for research or operational weather agencies on developing countries. Please check the first link I am including where it is explained whose services are free. In particular,  "DWD also provides lateral boundary data (up to 120h) to these services in real time via the internet free of charge up to four times daily, based on the analyses at 00, 06, 12 and 18 UTC." which can be useful for your projects. 

    In the second link I am providing you may check several operational weather services based on COSMO. There are mainly located on Europe but anyway in case you consider to use COSMO, it is interesting to compare the computational resources used on every case. There is also information about verification of the COSMO model including possible tools.

    Also the COSMO model is also used as a regional climate model, so in the third link you may find studies over Africa (also East Africa). They might be useful to identify specific problems of modelling to be ascertain on your region.

    Finally, please check the training stuff, I am also providing a link, and I have attached .pdf document (please check the Page 3, might be useful in your case).


    + 4 more attachments

  • Martin Jakob added an answer:
    Can anyone help me in calculating seasonal index (Walsh & Lawler,1981) using excel spreadsheet?

    Excel template will be helpful for me.

    Martin Jakob

    Hello Suman, I made a mistake in my thinking... my bad! However your suggestion was not the right one. I replaced the corrected Excel file.

    Just in case you want to know what I did in the template...


    Understanding the variables

    • i is a variable that stands for a month in the given year, it therefore can be a whole number between 1 and 12
    • xi is the average rainfall in the i-th month
    • R is the total (mean) rainfall in that year <-- here I mistakenly took the average


    According to the publication

    "... the (SI) was developed, which is simlpy the sum of the absolute deviations of mean monthly rainfalls from the overall monthly mean, divided by the mean annual rainfall:"


    Breaking down the Formula for the SI

    Step 1: calculate R as the sum of all xi (mean monthly rainfalls)

    Step 2: Calculate R/12

    Step 3: For each month subtract xi from R/12 --> if the value is negative, make it simply positive

    Step 4: Sum up all twelve values obtained in Step 3

    Step 5: Divide the sum from Step 4 by the calculated R from step 1


    In Excel

    Cells B3 to B14 are the mean monthly rainfalls. In B15 I calculate R which can be achieved by the following formula:


    I added a condition in which the value is only displayed if all values for xi are added


    In B16 I calculate the SI - I therefore simply apply steps 3 to 5 from above. Additionally I also add a condition to check whether B15 contains a value. This gives me the follwing (very long!) formula for B16



    I'm sure there is a way to make it easier but then again it works like that :-)

    Best, Martin

  • George Zittis added an answer:
    What are the geographic coordinate systems of the GHCN?

    What are the geographic coordinate systems of the Global Historical Climatology Network (GHCN) gridded data and your parameters (ellipsoid and datum)? I tried to open the air temperature gridded data of GHCN in the Quantum Gis (QGis) and the grid does not match correct region in Southeastern of Brazil.

    George Zittis

    I had a  global 0.5 degree netcdf file from GHCN. The output of cdo griddes command gives this:

    gridtype = lonlat
    gridsize = 259200
    xname = lon
    xlongname = Longitude
    xunits = degrees_east
    yname = lat
    ylongname = Latitude
    yunits = degrees_north
    xsize = 720
    ysize = 360
    xfirst = 0.25
    xinc = 0.5
    yfirst = -89.75
    yinc = 0.5

    I hope this helps a bit.

  • A. Robichaud added an answer:
    Can anyone tell me how to get AOD data from MODIS hieratic files?
    I want to make an analysis of atmospheric aerosols to relate with climatic factors (drought, etc.).
    A. Robichaud

    Do you know about NASA Giovanni tool ?

    It is easier to dig and get data for analysis

  • Gaurav Srivastava added an answer:
    How does the El-Nino/ENSO affect the Indian Monsoon?

    El-Nino/ENSO changes the atmospheric condition over the pacific region. But how does that change affect the Indian Monsoon. 

    Gaurav Srivastava

     There are many theories proving the significant simultaneous co-variability of ENSO and Indian Monsoon [Rasmusson and Carpenter 1982, Walker 1924 & Webster 1998].  Its the subsiding limb of the walker cell which is shifted  over India due to shift in the SST warming regions form West to East and Central Pacific ocean. 

    As Andy Turner (Sir) told that people have observed a weakening in the relationship in the recent times. Studies by Rajagopalan et al (2006) where they show how the pronounced warming over central Pacific is more likely to produce drought creating subsidence over India as compared to the El-Ninos when warming is more in the eastern Pacific regions.   Krishna Kumar et. al (1999) showed that due to the southeast ward shift in the walker circulation for the recent El-Ninos subsidence, weak subsidence was produced over Indian region and That is why ENSO-Monsoon relationship show a weakening in the trend for the recent period. 
    To me, everything above put together does not give a clean insight of how El-Nino affects Indian monsoon. 

    Though there are other school of thoughts as well which to me seem more promising as compared to theories given earlier. In a pioneering study done by Goswami and Xavier 2005 (GRL) it was proved that ENSO does affect the Indian monsoon by affecting the troposheric temperature gradient over the Indian monsoon region. Which ends up as the weak lower level monsoon flow and length of the long rainy season (LRS) is also altered by late onset and early withdrawal of Indian monsoon during ENSO years.

    Recently (2007) Shaman and Tziperman  have shown that ENSO-Indian Monsoon tele-connection comes from the ENSO related dynamics in the upper tropospheric mid-latitude regions. Warming over the central Pacific creates upper tropospheric divergence over the region which is source of the Rossby waves there. These Rossby waves are guided by North-African-Asian jet and associated positive vorticity anomalies do get flooded over the central Asian regions. Effect of these anomalous positive vorticity is pronounced cooling over those regions which ends up as weak temperature gradients in the upper troposphere over Indian region. This disrupts the monsoon flow over Indian region and we get a bad monsoon during EL-Nino years.

  • Arash Malekian added an answer:
    What do these error messages concerning gridded Green and Ampt infiltration in HEC-HMS mean?

    I am trying to set up a model in HEC-HMS using gidded Green and Ampt Infiltration as the loss method and ModClark for transformation but when I try to run it I get the following error messages: 

    ERROR 44850: Loss method "Gridded Green Ampt" is invalid for grid cells.
    ERROR 40501: An error occurred while initializing grid cell data for subbasin "W90". Parameter grid is missing or incomplete.
    ERROR 40441: Subbasin "W90" could not be initialized because the grid cells were missing or parameter data was invalid.

     I created a grid cell file using HecGeoHMS and I followed the instructions of the GeoHMS User Manual in order to create an ascii- file in the same coordinate system (SHG100) and then used this file as a mask to create all the gridded parameter information I need (Impervious area, initial water content, etc.) I also used this file to get my gridded precipitation data in the same resolution and the same extent as the grid cell file... 

    Then I transformed all these ascii-grids to dss files using the asc2dssGrid utility. 

    In case it is of importance: Before the error messages I also got those warnings:

    NOTE 40552: Grid cell file contained 4 invalid cells for subbasin "W140". Lost area equals 0.00008
    NOTE 40552: Grid cell file contained 3 invalid cells for subbasin "W90". Lost area equals 0.00003
    NOTE 40552: Grid cell file contained 2 invalid cells for subbasin "W80". Lost area equals 0.00006

  • Claire Harnett added an answer:
    How can I read GHCN precipitation daily files (format .dly) with MATLAB or R?

    I have downloaded daily climatological data from the Global Historical Climatology Network (GHCN), but it is provided in a not very common format such as .dly. I have found some R packages related to this, but apparently they are aimed at retrieving temperature measures. Any suggestions?

    Claire Harnett

    For any future confused people who stumble across this thread, I also found a toolbox here:

    It is open access and runs in matlab, letting you import your variables without actually writing any of your own script. Good user interface and would highly recommend!

  • Irfan Shakir added an answer:
    Can someone suggest an article on statistical downscaling of Global Precipitation Measuring Mission?

    Hi friends

    I am searching articles on statistical downscaling of Global Precipitation Measuring Mission.

    Irfan Shakir

    Thank you Mohammad

  • Jeremy Leung added an answer:
    Is there any work ranking the Madden-Julian Oscillation events in the past decades?

    The Madden-Julian Oscillation (MJO) event occurring earlier this year (2015) was said to be the strongest ever, based on its RMM index. I wonder if there is anyone ranking all the MJO events based on whatever criteria (e.g. RMM index, precipitation).

    Jeremy Leung

    That's a good idea Yi.

  • Sergey Victorovich Simonenko added an answer:
    What is the most accepted criterion to classify positive and negative Indian Ocean Dipole events?

    Indian Ocean Dipole (IOD) is commonly depicted by Dipole Mode Index (DMI). Most of the published research work relay on DMI to define IOD. But there are many disagreements in classification of IOD events among these publications. 

    What are the most accepted criterion of IOD events? Is there any source that provides a list of recent IOD events?

    Sergey Victorovich Simonenko

    .....Solar System.

  • Cynthia Evangeline Sellinger added an answer:
    What is the best programming language for solar radiation data processing?

    I just programmed macros in Excel, but I realize that sometimes (when the databases are very large and I would like to calculate many specific variables ) consumes many resources and computing time. I hear of people using Python, Fortran, C++, etc., but what is the best?

    Cynthia Evangeline Sellinger

    Interactive Data Language (IDL) works great for programming large data sets.  Not only can you use the built-in statistical packages, but this language handles a large, matrix of information with ease.

  • Uttam Ghimire added an answer:
    Can anyone suggest software for performing statistical downscaling on climate data?
    I'm looking for a step-by-step description for statistical downscaling.
    Uttam Ghimire

    For CMIP3 models, SDSM can be regarded as one of the easiest methods. However for CMIP5 models adopted in IPCC AR5, you cannot use that. 

  • Amrit Thapa added an answer:
    Do anyone have R code for distributing Temperature and Precipitation to each grid in DEM?

    I am trying to distribute temperature and precipitation data in mountainous catchment. I have a data of one of the station within the catchment and want to distribute on each grid of the DEM using lapse rate and vertical gradient. I am planning to use R software to do so. How can i do this?

    Amrit Thapa

    Dear Achut Parajuli,

    Thank you for your suggestions.

  • Michel M. Verstraete added an answer:
    Where can I get the FLUXNET tower data for India to measure the exchanges of carbon dioxide (CO2) between terrestrial ecosystems and the atmosphere?

    How much FLUXNET tower is installed in  India? How and where do I get the tower data for NPP model validation? 

    Michel M. Verstraete

    Dear Srikanta,

    Please visit the main web site of the FLUXNET programme at

    to find information on the locations, time periods and variables available through this initiative.

    According to the map of available sites

    there is only one FLUXNET station in India, located at the Central Rice Research Institute (CRRI):

    and this site has published data only in 2010, 2011 and 2012.

    In order to validate an NPP model, you will probably want to use data from other sites, with much longer time series.

    I hope this helps. Cheers, Michel.

  • Mark Žagar added an answer:
    Which GCM result is best for wind resources downscaling in complex rerrain like Nepal?

    I am currently doing thesis on "Impact of Climate Change on energy Generation from Wind Resources". 

    Mark Žagar

    Wind resource estimates in complex terrain require a forcing dataset, and a mesoscale/microscale model for downscaling. A forcing dataset will typically be one of the multi-decade atmospheric reanalyses (NCAR, ERA Interim, etc.) or a similarly long series of operational atmospheric analyses (e.g. publicly available NOAA GFS analyses). All of these can be used to drive a mesoscale model, like WRF, down to a resolution of a few kilometres. Subsequent downscaling can be then performed on limited areas using a CFD model, for example.

    In the same way as using past analyses for estimating the wind resources, one can use the climate prediction models to investigate future climate change impact on wind resources in complex terrain. The results will reflect changes in global/regional circulation patterns, but not the local features like forestation, glacier melting, etc., unless these surface characteristics are also being changed in the downscaling model according to the future predictions.

    As the previous posters have said, the resolution of the nowadays' regional climate models is perhaps still too low to provide reliable information about future wind resources in complex terrain. This is why I would propose the method described above in the meantime.

  • Kenneth M Towe added an answer:
    Is there any scientific community (even informal) especially dedicated to the climatology of small oceanic islands?

    I would greatly appreciate having feedback from scientists/groups specifically dedicated to the climatology of small oceanic islands worldwide (Including issues related with  as climate change, water, etc), having  information about their work, publications, etc.

  • Anice Garcia added an answer:
    Does anyone know a recent study addressing the spatialisation of temperature/precipitation/drought extreme events for the last 30 years?

    Hello, I have been searching for a study addressing climatic extreme events. However I could not find a study covering the last decades (especially from 1980 till now) at a global level. I do not mean I am looking for a a extreme event with a global impact, but the spatial distribution of different extreme events across time.


    Anice Garcia

    M.K.V. Sivakumar, R.P. Motha and H. Das (eds.) Natural Disasters and Extreme Events in Agriculture, Springer, Berlin (2005) 23–37.

  • Andreas Will added an answer:
    Is there any recent regional climate model for Africa?

    There are a number of regional climate models for different regions. I am interested to downscale global climate models based on regional climate mode for dynamical downscaling. Any suggestion is appreciated.

    Andreas Will

    Of course, there are many models and a broad band of evaluation results exhibiting a substantial spread.

    If you are not familiar with a mesoscale model, I cannot recommend conducting own simulations without an experienced cooperation partner. It's easy to produce numbers which don't describe the nature in an acceptable way.

    Using the CORDEX results first is strongly recommended.

    You find all models and the reference configuration for Africa on the CORDEX-AFRICA webpage. However, there are several attempts to simulate parts of Africa at higher resolutions by different groups. If you are interested in that, you probably need a non-hydrostatic model system like COSMO-CLM or WRF. E.g. at the CLM-Community webpage you may find a contact person who can answer your detailed questions.

    Good Luck, Andreas Will

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Climatology is the study of climate, scientifically defined as weather conditions averaged over a period of time, and is a branch of the atmospheric sciences.

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