DMAP Tool (Drought Monitor And Prediction)
We have utilized DMAP in several academic papers:
Estimation of meteorological drought indices based on AgMERRA precipitation data and station-observed precipitation data Predictive value of Keetch-Byram Drought Index for cereal yields in a semi-arid environment Rainfed wheat (Triticum aestivum L.) yield prediction using economical, meteorological, and drought indicators through pooled panel data and statistical downscaling Prediction of meteorological drought in arid and semi-arid regions using PDSI and SDSM: a case study in Fars Province, Iran
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You can access sample input files for download here: DropBox
What is DMAP (Drought Monitor And Prediction) software?
Drought is one of the most damaging natural hazards, and quantifying it requires more than a single rainfall total (Wilhite, 1993). Drought indices turn precipitation, temperature, evapotranspiration, soil moisture, streamflow, and vegetation-health data into a single comparable number, which is how scientists detect the onset, severity, and end of a drought event rather than relying on a subjective read of the weather (Zargar et al., 2011).
DMAP is built around three tabs that follow this workflow end to end. The Stations tab manages your network on an interactive map. The Data tab loads climate variables, either from Excel/CSV/text files (with automatic column and date-format detection), from NetCDF grids (with unit conversion and region/shapefile extraction), or by downloading data instantly from GPCC, NCEP/NCAR, CPC, NOAA STAR, CMIP6, or NASA AppEEARS, with no external file wrangling required. The Drought Indices tab then computes any of 19 indices for a single station or the entire network at once, using a built-in PET Calculator (Thornthwaite, Hamon, Hargreaves-Samani, or Penman-Monteith FAO-56) wherever evapotranspiration is needed.
Once an index is computed, DMAP doesn't stop at a chart: results feed into a dedicated View and Export Data window plus a suite of analysis windows — trend analysis, wavelet analysis, drought-event detection, severity-duration-frequency (SDF) analysis, teleconnection analysis, and multi-scale SPI/SPEI comparisons — so you can move from raw data to a publishable analysis inside a single tool.
Those 19 indices break down into four domains — meteorological, agricultural, hydrological, and remote-sensing/vegetation-based drought — grouped below by which tab's inputs they need:
Subsection
SPI (Standardized Precipitation Index, McKee et al. 1993, 1995
DI (Deciles Index), Gibbs and Maher, 1967
PN (Percent of Normal Index), Willeke et al. (1994)
CZI (China-Z Index), Wu et al. (2001)
MCZI (Modified CZI), Wu et al. (2001)
EDI (Effective drought Index), Byun and Wilhite (1999)
RAI (Rainfall Anomaly Index), van Rooy (1965)
ZSI (Z-score Index), Palmer (1965)
SPEI (Standardized Precipitation Evapotranspiration Index), Vicente-Serrano et al., 2010 and Salehnia et al., 2020
RDI (Reconnaissance Drought Index), Tsakiris and Vangelis, 2005
PDSI (Palmer Drought Severity Index), Palmer (1965) and Dehghan et al., 2020
PHDI (Palmer Hydrological Drought Index), Palmer (1965)
PDSI-SC (Self-Calibrated Palmer Drought Severity Index), Wells et al., 2004
KBDI (Keetch-Byram Drought Index), Keetch and Byram, 1968
ARI (Agricultural Rainfall Index), Nieuwolt, 1981
ETDI (Evapotranspiration Deficit Index), Narasimhan and Srinivasan, 2005
SMDI (Soil Moisture Deficit Index), Narasimhan and Srinivasan, 2005
SDI (Streamflow Drought Index), Nalbantis and Tsakiris, 2009
SWSI (Surface Water Supply Index), Garen, 1993
VHI (Vegetation Health Index), Kogan, 1995
NMDI (Normalized Multiband Drought Index), Wang and Qu, 2007
VSDI (Visible and Shortwave infrared Drought Index), Zhang et al., 2013
On the Drought Indices tab, selecting an index automatically shows only the inputs it needs (for example KBDI only activates once daily rainfall and Tmax are loaded), then runs the calculation across the whole network at once. Results can be viewed as BoxPlot, Linear, or Columnar charts with an optional H-Line marker, and any chart can be saved directly as an image.
To project future drought, load CMIP5/CMIP6 model output (historical or an SSP/RCP scenario) through the Data tab's NetCDF or Download sub-tab, then calculate the same drought indices on that future-period data. Because DMAP applies identical index logic to both observed and projected data, historical and future drought severity are directly comparable.
DMAP is free to use for station management, data import, and every analysis window; a license is only required to run the index calculation itself and to submit CMIP6 or NASA AppEEARS download jobs.
Watch Drought Course Videos: Drought Lesson
PDSI - Palmer Drought Severity Index
Watch how to calculate the Palmer Drought Severity Index (PDSI) in DMAP: entering Surface Soil water capacity and Available Water Capacity for each station, computing evapotranspiration, running the index, and reading the resulting drought severity chart.
How can I use DMAP tool to predict drought?
To forecast drought with DMAP (Drought Monitor And Prediction), start with future climate projections, typically CMIP5 or CMIP6 global climate model output under a historical or SSP/RCP scenario, spanning out to the year 2100. You can download CMIP6 data directly from the Download sub-tab, or bring in your own CMIP5/CMIP6 NetCDF files (ideally bias-corrected to station scale first, for example with SD-GCM ).
Load that future-period data through the Data tab exactly as you would observed data, then calculate the same drought index on it from the Drought Indices tab. Because DMAP applies identical index logic and thresholds to both periods, you can plot projected drought severity right alongside the historical record for the same station or region.
This lets you compare how often, how severely, and for how long a location is projected to experience drought under a given climate scenario, versus its observed history, using the same trend, severity-duration-frequency, and drought-event analysis windows available for observed data.
Type of input file in DMAP tool
The Data tab loads climate data through three sub-tabs, so you're not limited to one file format:
Excel / Text / CSV: Station-based data (xls, xlsx, txt, csv) with automatic column and date-format detection.
NetCDF grids: Gridded datasets (nc, nc4), including CMIP5/CMIP6 model output, with built-in unit conversion and the ability to extract a single point or the mean of a region/shapefile.
Instant download: No file to prepare at all — pull precipitation and temperature data directly from GPCC, NCEP/NCAR, CPC, or NOAA STAR, request a CMIP6 scenario, or fetch vegetation-based data for VHI/NMDI/VSDI from NASA AppEEARS.
All three paths feed the same station network and the same 19 drought indices, so the input format you choose doesn't limit which analysis you can run afterward.
Calculation of each index in DMAP Software
In DMAP, the equations for each index were implemented directly from the original paper that introduced it, along with all the relevant details. The primary references for each index are listed in the reference section below.
It's important to note that each index requires specific variables and time scales. For instance, the KBDI index requires daily Tmax (maximum temperature) and Rainfall data. Once you load daily rainfall and Tmax for a station, the KBDI index becomes selectable on the "Drought Indices" tab.
Severity of Drought in DMAP
In DMAP, users can determine the severity of drought using a customizable threshold, which varies for each index. For instance, in the case of the SPI (Standardized Precipitation Index), the typical threshold might be less than -0.99 or can also be set to zero. On the other hand, for the KBDI (Keetch-Byram Drought Index), the threshold could be set to values greater than 200 or 250.
When utilizing DMAP to calculate drought severity for the SPI index (values falling below the specified threshold), the following steps are followed:
Calculate S0 = SPI - border, where "border" is the specified threshold value.
Identify drought events as instances where S0 is less than zero.
Each drought event starts when S0 first becomes less than zero.
Each drought event continues as long as S0 remains less than zero.
Calculate the duration of each drought event, which corresponds to the number of days between the start and end of the event.
Determine the severity of each drought event by calculating the cumulative sum of the absolute values of S0 during that event, i.e., the sum(|S0|) between the start and end of the drought event.
Tips and Points
In DMAP V2.1, input files can be in various formats, including xls, xlsx, txt, and csv. NetCDF (nc and nc4) format is also supported, with a feature that extracts data for a specific point or area from a NetCDF file. If a region is selected, the tool calculates the mean value for that region.
DMAP includes a useful option to convert the unit of data in NetCDF files. For instance, it can convert flux values to mm values, which is particularly beneficial for models like CMIP5 or CMIP6.
It's important to note that input data can be in daily, monthly, or yearly timescales. However, if yearly data is entered, the software won't compute drought index values on a monthly scale.
Some indices, such as KBDI and EDI, require daily data. If monthly or yearly data is used as input, the calculation of these indices won't be possible, and the corresponding icons will be deactivated.
DMAP V2.1 is capable of computing 19 drought indices spanning meteorological, agricultural, hydrological, and remote-sensing/vegetation-based droughts. Each index has specific requirements regarding input data.
In the station list of the Drought Monitor And Prediction (DMAP) tool, there are 6 input items available. However, the number of inputs required depends on the selected index. For all rain-based indices such as SPI, DI, CZI, MCZI, etc., you only need to enter the names of the stations if you choose not to use the Netcdf file as input. However, if you decide to use the Netcdf file, you will also need to provide the latitude and longitude of the stations. When calculating the PDSI index, you will need to enter the name, latitude, Surface Soil, and Available Water Capacity. For the KBDI Index, you will need to input the name and Field Capacity. If you choose to extract data from Netcdf files using the list of stations, you will need to enter both the latitude and longitude along with the names of the stations to facilitate the data extraction process.
The first tab in the tool allows users to enter variables as a time series (daily, monthly, or yearly). The number of input variables depends on the index. For all rainbased you need to enter just rainfall.
Depending on the selected index, drought calculations can be performed at various time scales, including daily, monthly, yearly, and moving averages. But the moving average is not active for all indexes.
For evapotranspiration, DMAP includes a built-in PET Calculator offering four methods: Thornthwaite, Hamon, Hargreaves-Samani, and Penman-Monteith (FAO-56). Thornthwaite and Hamon need only temperature and latitude, while Hargreaves-Samani and Penman-Monteith use additional variables such as min/max temperature, solar radiation, humidity, and wind speed. Alternatively, you can skip the calculator and enter your own evapotranspiration values manually. The result is used wherever an index, such as SPEI, PDSI, or PHDI, requires evapotranspiration as input.
When calculating SPEI with computed evapotranspiration(SPEI1), users only need to provide the value of Latitude in decimal numbers and temperature as Tave in the Input time series. For KBDI calculation, the user must input the value of Field Capacity (FC) in mm.
For calculation of PDSI and if you apply the amount of computed evapotranspiration, then you need to fill three items, including Surface Soil water in mm(usually is 25mm), Available Water Capacity (AWC) in mm, and Latitude in decimal number.
In the case of RDI calculation, users have the option to select the checkbox for "Standardized RDI."
DMAP V2.1 includes a graph plotting panel with three types of graphs: BoxPlot, Linear, and Columnar. Users can customize their graphs by selecting colors or using the H-Line (horizontal line) option, and can save any chart directly as an image.
Quick Guide
I-
Go to the "Data" tab's "Excel" sub-tab and open the list of stations, loading the corresponding latitudes and longitudes.
Depending on the index you want to calculate, enter the required values for each station as follows:
PDSI --> Input SS, which signifies the available water capacity of the surface layer for each site (typically in mm, often around 25mm), and AWC, indicating the available water capacity of the underlying layer for each site (in mm).KBDI --> Input Field CapacitySPEI, PDSI, PHDI (evapotranspiration) --> If you don't have measured evapotranspiration, open the PET Calculator and choose Thornthwaite, Hamon, Hargreaves-Samani, or Penman-Monteith (FAO-56); Thornthwaite and Hamon need only latitude and temperature, the other two need additional variables.
You can consider the SS values as 25mm
Select the tab corresponding to the variable you need. By inputting each variable, one or several indexes will become calculatable:
Rainfall --> SPI, CZI, ZSI, EDI(if your data is daily), PN, DI, RAI, MCZIRainfall and Tave --> PDSI, PHDI, SPEI1(In this indexes calculate PET by Tave)Rainfall and Tmax --> KBDI. Your data(Rainfall, Tmax) should be in dailyRainfall and PET --> SPEI, PHDI, RDI, ARI, PDSI1PET and AET --> ETDISoil Moisture --> SMDIStream Flow --> SWSI, SDI
Select your Excel file and the corresponding sheet. Manually set the column headers, or use the "Auto-Fill Col-Head" button. If using the auto-fill option, ensure all column headers are correctly selected, and manually select the "Date" column.
The name of stations in the list should be same as in the first row of your data
After you click on "Auto-Fill Col-Head" check the selection of all column header
Select the "Date" column manually.
Once the loading is complete, proceed to calculate the index.
II-
Go to the "Data" tab's "NetCDF" sub-tab, select your NetCDF files, and verify the names of variables, units, and calendar information. If needed, you can view the NetCDF content using the "View Database" option.
Depending on your preferences, choose one of the following options:
If you have stations in the list, use the first RadioButton.
If not, input the stations manually in each table or provide a file with station details. Alternatively, use the "Use a Region" RadioButton, entering the start and end latitudes and longitudes for your region. The tool will create a station list based on the cells, considering each cell as one station.
Save the data. If you have loaded the variable in the first tab, it will be replaced. For saving, select the name of the variable and the unit converter. If no conversion is needed, choose "Multiply by 1."
III-
Precipitation and temperature archives: GPCC, NCEP/NCAR, CPC, and NOAA STAR.
Future climate scenarios: CMIP6 (via the "Open CMIP6 Window" button).
Vegetation/remote-sensing data for VHI, NMDI, and VSDI: NASA AppEEARS.
When the loading is complete then you can calculate the index in the "Drought Indices" tab.
Regional Drought Monitor
Watch how to monitor drought across an entire region or network of stations in DMAP: importing NetCDF grids or a station network, selecting a drought index, and mapping drought severity across the study area rather than a single point.
References:
Byun H R, Wilhite D A. 1999. Objective quantification of drought severity and duration. Journal of Climate, 12(9): 2747-2756.
Garen DC, 1993. Revised surface-water supply index for western United States, J. Water Resour. Plann. Manage. 1993.119:437-454.
Gibbs, W.J., and Maher, J.V. 1967. Rainfall Deciles as Drought Indicators, Bureau of Meteorology bulletin, No. 48. Commonwealth of Australia: Melbourne; 29.
McKee T B, Doesken N J, Kleist J. 1993. The relationship of drought frequency and duration to time scales. In: Proceedings of the 8th Conference on Applied Climatology. Anaheim, CA: American Meteorological Society, 179-184.
McKee T B, Doesken N J, Kleist J. 1995. Drought monitoring with Multiple Time scales. In: Proceeding of the 9th Conference on Applied Climatology. Dallas, TX: American Meteorological Society, 233-236.
Nalbantis, I., and Tsakiris, G. 2009. Assessment of hydrological drought revisited. Water Resour Manage. 23:881-897
Nieuwolt S, 1981. Agricultural droughts in Peninsular Malaysia. Malaysian Agricultural Research and Development Institute, Serdang, p: 16.
Narasimhan, B., and Srinivasan, R. 2005. Development and Evaluation of soil Moisture Deficit index and Evaporation Deficit Index for Agriculture of Drought Monitoring, Agricultural and Forest Meteorology, 133-69-88.
Palmer WC, 1965. Meteorological drought: US Department of Commerce, Weather Bureau Washington, DC, USA. 45, 58.
Salehnia N, et al., 2017. Estimation of meteorological drought indices based on AgMERRA precipitation data and station-observed precipitation data. J Arid Land (2017) 9(6): 797-809. Drought AgMerra
Tsakiris G, and Vangelis H, 2005. Establishing a Drought Index incorporating evapotranspiration. European Water. 9/10:3-11
Van Rooy MP, 1965. A rainfall anomaly index independent of time and space. Notos 14:43-48
Vicente-Serrano SM, Beguerra S, and Lopez-Moreno JI, 2010. A Multi-Scalar Drought Index Sensitive to Global Warming: The Standardized Precipitation Evapotranspiration Index - SPEI. Journal of Climate 23(7):1696-1718, DOI: 10.1175/2009JCLI2909.1
Wilhite DA, 1993. The enigma of drought. Drought Assessment, Management, and Planning: Theory and Case Studies. Kluwer Academic Publishers, Boston, Ma. pp. 3-15.
Willeke G, Hosking J R M, Wallis J R, et al., 1994. The national drought atlas. In: Institute for Water Resources Report 94-NDS-4. U.S Army Corp of Engineers, CD-ROM. Norfolk, VA.
Wu H, Hayes M J, Weiss A, et al., 2001. An evaluation of the Standardized Precipitation Index, the China-Z Index and the statistical Z-Score. International Journal of Climatology, 21(6): 745-758.
Zargar A, Sadiq R, Naser B, Khan FI, 2011. A review of drought indices. Environ. Rev. 19: 333-349 (2011). Doi: 10.1139/A11-013
The license of this tool is applicable for one year of using and you can renew it by pay 20% of the price for the new year.