Geoscience Reference
In-Depth Information
implements this data model [WOO 06]. The model describes climate science data
(e.g. observational data, model runs) at the level of the actual data values; CSML is
not a high-level discovery metadata model [LOW 09]. An example of a simplified
structure of an OGC compliant web service for integration of
meteorological/climatological data in geospatial services or applications is shown in
Figure 1.3.
Another major OGC initiative with increasing interest from meteorology is
Sensor Web Enablement (SWE). The ultimate goal of SWE is to make all kinds of
sensors discoverable, accessible, and controllable via the web, which should result
in “plug-and-play” web-based sensor networks. Beside others, SWE include Sensor
Observation Service (SOS), Sensor Planning Service (SPS), and Sensor Alert
Service (SAS). SOS aims to provide access to observations from sensors in a
standardized way that is consistent for all sensor systems, including remote,
in situ
,
fixed and mobile sensors.
As mentioned previously, the time dimension is an important domain in
meteorology and climatology not adequately covered by GIS (see e.g. [WOO 05]).
Moreover, climatology and weather forecast are highly interested in slices of time,
showing climate fields on axes of latitude and time or longitude and time. Such
diagnostic slices are required in future GIS standards. In addition to the time
dimension, the representation of gridded meteorological fields could result in
problems. For instance, meteorological grids can be non-regularly spaced or, in the
case of models formulated in spectral coordinates, could have fewer longitudinal
grid-points towards the poles. These shortcomings need to be addressed in the future
by additional cooperating standardization work between GIS and meteorology.
1.1.5.
Spatial reference for climate data
The position of climatological/synoptic station has to be measured in the World
Geodetic System 1984 (WGS-84) or Earth Geodetic Model 1996 (EGM96). The
coordinates of a station includes [WMO 08]:
a) the latitude in degrees with a resolution of 1 in 1,000;
b) the longitude in degrees with resolution of 1 in 1,000;
c) the altitude of the station above mean sea level to the nearest meter.
The elevation of the station is defined as the altitude above mean sea level of the
ground on which the rain gauge stands or, if there is no rain gage, the ground
beneath the thermometer screen. If there is neither a rain gauge nor screen, it is the
average level of terrain in the vicinity of the station. If the station reports air
pressure, the elevation of air pressure sensor must be specified separately.
Within the last few years, the increasing number of spatial modeling tools with
increasing spatial resolution used in meteorology and climatology also enforced the
pressure on the accuracy of station coordinates. Previously station coordinates were
digitized from topographical maps; currently, station coordinates are surveyed by
