Utilizing online resources for climatic research [part 2]

Introductory words:

Climate change and its impact assessment has strike through a great attention these days, especially after  wining the Nobel peace prize in 2007 by AL Gores team with IPCC. Huge number of universities and research organizations started working on climate impact assessment. Like geographic data, climatic data’s are not as straight forward to extract from online resources. Various reasons involved for this problem, most often climatic data’s are uploaded in gridded points with various temporal and spatial scale.  Therefore, in this post we are going to see where we can get online data for climatic research and how we can utilize them. One more time all those data’s are completely” FREE OF CHARGE”

[1] National Climatic Data Center, USA (NCDC) 

National climatic data center for USA provides climatic data on various spatial and temporal scales for entire globe [1A]. NCDC is the world's largest active archive of weather data. NCDC produces numerous climate publications and responds to data requests from all over the world. NCDC operates the World Data Center for Meteorology which is co-located at NCDC in Asheville, North Carolina, and the World Data Center for Paleoclimatology which is located in Boulder, Colorado. Here we will be focusing time series in daily time step. It is to be noted that there are lot of variables available in the website but we will be focusing precipitation temperature (min and max) for this specific post. We will only look at Summary of the Day) [1B]. Summary of the Day (Office of Hydrology Format) is historical data set DSI-9655 archived at the National Climatic Data Center (NCDC). The Office of Hydrology (O/H) format was designed for use in implementing the National Weather Service River Forecast Service (NWSRFS) nationwide, and for calibration of hydrologic models. Parameters for these summaries of the day data set include: temperature, precipitation, winds, surface pressure, evaporation, and snow depth. The period of record is 1948-1976.

[1A] NCDC data description

[1B] Summary of the Day (Office of Hydrology Format)

2. Precipitation data from TRMM website

The Tropical Rainfall Measuring Mission (TRMM) is a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA) designed to monitor and study tropical rainfall A good number of researches have been done to assess the relativity of TRMM data for and found reliable for data sparse region, together with that a large no of studies applied TRMM data for various purpose among them, development of agricultural information system for crop production and irrigation need . The Tropical Rainfall Measuring Mission aims to monitor tropical and subtropical precipitation and to estimate its associated latent heating (GES DISC, 2010). The daily product TRMM 3B42 was used in this study. The purpose of the 3B42 algorithm is 5 to produce TRMM-adjusted merged-infrared (IR) precipitation and root-mean-square (RMS) precipitation-error estimates. The version 3B42 has a 3-hourly temporal resolution and a 0.25_ by 0.25_ spatial resolution. The spatial coverage extends from 50_ S to 50_ N and 0_ to 360_ E. The temporal scale considered for this video clip is for daily.

Citations:

[2A] TRMM website link

[2B] Performance testof TRMM data for Vietnam river basin.

[2C] Agriculturalinformation system based on TRMM data.

3. Working with netCDF data

NetCDF is a data abstraction for array-oriented data access and a software library that provides a concrete implementation of the interfaces that support that abstraction [3A]. The implementation provides a machine-independent format for representing arrays. Although the netCDF file format is hidden below the interfaces, some understanding of the current implementation and associated file structure may help to make clear why some netCDF operations are more expensive than others.For a detailed description of the netCDF format, see File Structure and Performance. Knowledge of the format is not needed for reading and writing netCDF data or understanding most efficiency issues. Programs that use only the documented interfaces and that make no assumptions about the format will continue to work even if the netCDF format is changed in the future, because any such change will be made below the documented interfaces and will support earlier versions of the netCDF file format.ArcGIS and MATLAB has in built library for dealing with netCDF files [3B][3C].

Citations:

[3A] NetCDF in wikipedia

[3B] Working with netCDFdata in ArcGIS 

[3C] Working withnetCDF data in MATLAB

4. Climatic data for Europe [PRUDENCE Project]

PRUDENCE stands for Prediction of Regional Scenarios and Uncertainties for Defining European Climate Change Risks and Effects (Christensen et al. 2002) [4A]. A large number of decision making process has been done with the climate model generated variables [4B], among them Schelali et al (2007)[4C]  studied hydropower influence. Beniston et al (2010) studied impact assessment of climate change on mountainous watershed due to prevailing climate . The main objective of the PRUDENCE project was to provide high resolution climate change scenarios for Europe at the end of the twenty-first century by means of dynamical downscaling (regional climate modeling) of global climate simulations. Prudence project provides two time slices one called control period with the time series of 1960-1990 and the other one is scenario period 2070-2100.

Citations:

[4A] Prudence project web site

[4B] Research based on Prudence model from springerlink

[4C] Future energystudy in Switzerland based on prudence data.

In the next post we will see how to build an open source hydrological model name SWAT with all the Geographic and climatic data obtained from various sources. So please keep tuned.

Acknowledgement: Support from Dr.Chetan Maringanti and Dr. Mamuka Gvilava were duly acknowledged for preparing this post. Especially on the script writing part and compiling the information’s for possible data sources.

Utilizing online resources for hydrological research [Part 1]

Introductory words:

Many of us familiar that online resources available for water resources/hydrological research but the same way many of us don’t really know where and how to get those data easily in a usable format. Various problems we face when we desperately need some data, among them finding the exact site and getting the exact data is most notable. Often it happens  that we become ambiguous to see too many information given in the web site and we could not find the required one that we need. Here in this post we will see how to get some environmental data needed to build a hydrological model and process them in a usable format. There are varieties of data available but we will focus only the listed below. Once again these data`s are completely FREE OF CHARGE!!

[1] Administrative Area Map (Shape file)

[2] Digital Elevation Model (DEM)

[3] River Network

[4] Land use Map

[5] Digital Soil Map

[1] Administrative Area Map

Administrative area maps are very useful to when we want to have basic information for some specific region. It is often difficult to find administrative area of developing countries or some specific island therefore a group of researcher made it possible geo referencing all the region of the entire earth and putting them all together in the GADM website [1A]. The file formats are ESRI shape file [1B], or (.kmz) files for Google earth plugin.

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Citations:

[1A] Global Administrative Area website

[1B] About shape file [ESRI website]

[1C] Use of shape files [Based on wiki]

[2] Digital Elevation Model

Digital elevation model (DEM) represents the elevation of Earth’s surface, including features (vegetation, buildings, etc.).A DEM can be represented as a raster a grid of squares, also known as a height map when representing elevation [2A]. They are very useful for watershed/hydrological modeling [2B]. Especially they play significant role for flood mapping and modeling spatial extent of food [2C]. Traditionally elevation was derived by direct survey of the land, and then photogrammetry techniques allowed for terrain extraction with a pair of images with stereoscopic techniques. Today, highly accurate digital elevation can be achieved with light detection and ranging (LIDAR) and interferometry synthetic aperture radar (IfSAR). The SRTM digital elevation data, produced by NASA originally, is a major breakthrough in digital mapping of the world, and provides a major advance in the accessibility of high quality elevation data for large portions of the tropics and other areas of the developing world [2D]. Beside academia DEMs are commercially used for geographic analysis especially urban and regional planning [2E]. Globally available DEMS has approximately 1 km resolution from GTOPO30 and 90 m accuracy from the Shuttle Radar Topography Mission (SRTM) [1].

There are various ways we can download DEM from SRTM site but I found the easiest way of quick download using Google earth plugin [2F]. Here is the video clip to have quick access of SRTM DEM and processing steps to make better use of it.

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Citations:

[2A] Digital Elevation model basicintroduction [wiki]

[2B] Application of Digital ElevationModel for hydrological analysis [ESRI web]

[2C] The use of digitalelevation models for flood hazard mapping:

[2D] SRTM 90m Digital Elevation Databasev4.1

[2E] Applying GIS for populationdistribution under traffic impacts

[2F] CGIAR website with SRTM data

[3] River Geometry Map:

Steam geometry maps are extremely important for flood modeling and management. [3A]. River network is useful for basin delineation [3B]. HydroSHEDS is a mapping product that provides hydrographic information for regional and global-scale applications in a consistent format [3C] It offers a suite of geo-referenced data sets (vector and raster) at various scales, including river networks, watershed boundaries, drainage directions, and flow accumulations. HydroSHEDS is based on high-resolution elevation data obtained during a Space Shuttle flight for NASA's Shuttle Radar Topography Mission (SRTM). The goal of developing HydroSHEDS was to generate key data layers to support regional and global watershed analyses, hydrological modeling, and freshwater conservation planning at a quality, resolution and extent that had previously been unachievable. Available resolutions range from 3 arc-second (approx. 90 meters at the equator) to 5 minute (approx. 10 km at the equator) with seamless near-global extent.

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Citations

[3A] River flow forecasting usingartificial neural network

[3B] watershed delineation process[ArcGIS website]

[3C] HydroSHED web site

[4] Land cover map:

Land use maps often called zoning maps are basically derived from the satellite images and classifying them [4A]. Wide application of land use maps mostly for demographic features and Eco hydrological research[4B ]. They are often used for impact assessment of climate change due to vegetation change and demographic features [4C]. Environmental impacts and land at risk from land degradation such as salinity, flood, drought, and erosion studies can be done with land use maps. Land use maps are prepared by several government agencies, for a variety of reasons. Individual groups and organizations can also generate maps with land use information. Often, such maps are publicly available, so that people who are interested in land use trends can access them. For global application European Space Agency (ESA) provides maps in different time slice. They 

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citations

[4A] About land use map [wiki]

[4B] Land cover maps for ecologicalresearch

[4C] The Importance of Land-CoverChange in Simulating Future Climates

[5] Digital Soil Map

Digital soil map provides type of soil and their physical properties. Soil properties have immense importance for agricultural productivity and application of fertilizer. Soil map can be prepared by survey or classifying the remote sensing images [5A] robust application of soil maps is most often related to irrigation requirement and scheduling. Food and Agricultural Organization of united nation provides soil map with 1:10000 scale classifying 6998 soil classes for entire world. This can be obtained from the geo network web portal of FAO [5B]. Organic and inorganic components are including with the attribute table provided by FAO which is very useful for agricultural research [5C].

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Citations:

[5A] Soilsurvey and mapping using remote sensing

[5B] Geo network web portal for FAOsoil map

[5C] Description of organic and inorganic comment of soil properties from FAO.

Concluding remarks [For part: 1] 

Few issues needed to be discussed, among them projection system and resolution of data needs attention. In most cases the standard projection system is GCS WGS 1984 where the distances are calculated on Arc second. Usually 1 degree equals to 100 km. Since I used ArcGIS they have a default projection of GCS WGS 1984. There might be some error messages or dis placement of maps if the projection system is not similar with the data frame and the extracted data from different sources!!

Here it ends the part 1 of extraction of freely available online geographic data for Environmental/Hydrological/Geographical research, the next section I will be focusing CLIMATIC data [Precipitation, Temperature, Wind speed Solar radiation etc etc.] freely available. So keep tuned....