Case Studies

Introduction

• Meteorological data from the Israel Meteorological Service.
  Daily rain observations for the period 1989-2000 are available for download from the ISA-MEIDA site (the exact years available are changed periodically), and data for other years is available on request.
  The Meteorological Service data can be used to track the weather and the climate in Israel. For example, an issue of great concern is the amount of rain, and whether rainfall in Israel is decreasing.
  For a rain-study example the unusual 1991-1992 winter was chosen. This winter had several events of large amounts of precipitation within a short time.
  The rain measurements in Tel-Aviv during this winter are shown in the Excel file containing the data from the Meteorological Service station in Tel-Aviv.
  The specific rain event on 24 February 1992 was chosen for a more detailed study.

• ISA-MEIDA has radiosonde data from Beit-Dagan. This data is available on request, for research purposes only.
  The radiosonde measurements from Beit-Dagan for the date of the rain event previously described are shown in the Radiosonde Excel.

• Forecasts from the Tel Aviv University Weather Research Center (TAU WeRC).
  Daily Forecasts with the Tel-Aviv University Mesoscale Model are available from November 2000 and onwards.
  The forecasts are available as GIF maps of sea-level pressure, total precipitation, 850 mb temperature and wind, and planetary boundary layer height. There are also available, since June 2001, specific hourly predictions of temperature, humidity, precipitation, and wind, for Jerusalem, Beit-Dagan, Beer-Sheva, and Hadera.
  Model output files in GrADS format (approximately 15MB each file), and all past forecast maps can be reached through the ISA-MEIDA site.
  The model outputs include all the above parameters and many more, for every grid point. The grid interval is approximately 20 km, and there are 10 height levels.
  As an example the fine-grid forecast GrADS file for April 1st 2001 can be reached from this page, along with its appropriate control file.

• AVHRR satellite images over Israel.
  ISA-MEIDA holds several hundred processed AVHRR images of Israel, for the period from October 1996 to March 2000.
  The satellite images are available as JPG images, for immediate viewing, and as HDF files which include the entire five-channel satellite data.
  Through ISA-MEIDA and the EDG (see the Main page) it is possible to access the entire NOAA archive of AVHRR images, some samples of which are here, here, here, and here.

• ISA-MEIDA was contacted from the Ministry of Agriculture regarding climatic comparison between two adjacent regions of Israel ; Ramat-Ha'Negev and the Arava.
  Three of the meteorological stations whose data is available on-line from ISA-MEIDA were relevant : Sde Boker, Sedom, and Eilat. For possible additional stations, the caller was referred to the Israel Meteorological Service, and the Israel Hydrological Service, including recommendations about who to contact there.
  Our caller also requested sources for aerial or satellite photographs, and we recommended the following :
  
  • Vegetation cover is usually a product from satellite photos and not easily seen directly from the photos.
    Therefore a map might be a better solution. The Nature Conservation Authority has maps which might be of use, as given in the list by the GIS center at the Hebrew University (choose Services, and then Meta Data, or go directly to the RaShut HaTeva link).
  • For satellite derived vegetation cover indices a quick and simple source is Visible Earth, with vegetation index photos at http://visibleearth.nasa.gov/Biosphere/Vegetation/Vegetation_Index.html.
    However, this is not an archive, only samples, so might not be suitable for purposes of climatic comparison.
  • The AVHRR instrument, which is carried on NOAA satellites, is used to derive the Normalized Difference Vegetation Index (NDVI).
    Look in the Pathfinder Advanced Very High Resolution Radiometer (AVHRR) Land (PAL) Data to read about the available data sets, order, and download.
    This site also provides images, which are easy to use and do not require special software to display.
    An alternative for Europe is the European Vegetation Index (NDVI) site. The European data can also be found through a search for "vegetation index" using the search engine at http://eoweb.dlr.de:8080/servlets/welcome (in order to retrieve some types of data a registration is required, but registration is free).
    Both data sets can be ordered through the EOS Data Gateway.
  • A more modern instrument is MODIS on NASA's TERRA satellite. However, an ability to work with HDF files is required in order to use the data.
    An explanation of the MODIS vegetation index is given in http://gaea.fcr.arizona.edu/projects/modis/index.html.
    For MODIS land cover see http://geography.bu.edu/landcover/index.html.
    MODIS data can be requested through the EOS Data Gateway, and there is a summary and explanation of how to get the MODIS vegetation index on http://edcdaac.usgs.gov/modis/mod13a1.html.
  • For air photographs the best source is the Survey of Israel ("Merkaz Mipui Yisrael") .
    The Survey is the official depository for air photographs of Israel, going back to the beginning of the 20th century.

• ISA-MEIDA received an inquiry from an M.Sc. student in the Synoptic Laboratory at the Hebrew University of Jerusalem.
  The student required land cover information for his thesis, and asked about possible sources of information.
  The EOS Data Gateway can be intimidating at first glance, and therefore an EDG tutorial including an example was written by ISA-MEIDA. Also, as part of the policy of reaching Earth-Science researchers in Israel, a visit and demonstration were arranged.
  Links for Vegetation Cover Indices appear in the previous sample case, and can also be found through EDG, as was shown in the demonstration.
  The EDG is designed as an order and retrieval system for data sets already familiar to the researcher, but it is possible to use it as a general search engine, by starting a search with the parameter option. In this case, for example, the parameter list includes the entries "Land Cover", "Vegetation Cover" and "Vegetation Index". By choosing these parameters and then checking which data sets are available for them, EDG can be used to look for possibly suitable data.
  For example, after choosing the "Vegetation Cover" parameter, clicking on the data set option shows a list of data sets such as Boreas Forest Cover, European Vegetation Index derived from NOAA AVHRR, and MISR level 2 Surface Parameters.
  Choosing the "Vegetation Index" parameter and clicking the data set option shows a list of data sets such as AVHRR Pathfinder Land 10 day Mosaics,European Vegetation Index derived from NOAA AVHRR, and MODIS TERRA Vegetation Indices.
  Of-course, the researcher has to read about the data-sets in order to determine if they are suitable for his/her purposes.

• Meteorological information over long periods is also frequently requested. An M.Sc. student from UCLA downloaded the stations available from the ISA-MEIDA site, and also contacted ISA-MEIDA for more stations.
  ISA-MEIDA prepared and sent him the Daily surface observations from the Israel Meteorological Service for several stations, for the period from 1970 to 1999.