Difference between revisions of "Data"
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==Greenland== | ==Greenland== | ||
These are 5km resolution, NetCDF files of Greenland gathered from various data sources and interpolated, when necessary, onto the same grid using polar stereographic projection. | These are 5km resolution, NetCDF files of Greenland gathered from various data sources and interpolated, when necessary, onto the same grid using polar stereographic projection. | ||
| − | [[Image: | + | [[Image:Greenland_surfvel.png|thumb|right|300 px|Antarctica: Ice surface temperature draped over ice surface elevation.]] |
{| class="wikitable" style="margin: 1em auto 1em auto" | {| class="wikitable" style="margin: 1em auto 1em auto" | ||
Revision as of 20:10, 3 March 2009
Contents |
Overview
Data products used in the CISM efforts are distributed on this page. All data are encapsulated in the netCDF format, and conform to CF 1.3 naming conventions. On this page you will find
- Present day Antarctica data sets. Right now this consists of
- Surface elevation
- Bed elevation
- Surface temperature
- Accumulation rate
- Basal Heat Flux
- Surface velocity
- Present day Greenland data sets. Right now this consists of
- Surface elevation
- Bed elevation
- Surface temperature
- Precipitation
More information about the data sources, projection, and grid are found below. Soon we will be adding data sets reflecting
- Antarctica after a 200,000 year model spin-up (run to equilibrium with a climate forcing from ice core data).
- Greenland after a 200,000 year model spin-up.
- 100 years of climate forcing for Antarctica and Greenland.
NetCDF Viewers
There are several available viewers for NetCDF file types. Some suggested ones for linux and mac users is Ncview. Ncview provides a straightforward and simple GUI to quickly view NetCDF files. More robust programs include the IDV program that can be installed on a windows operating system. IDV has a sharper learning curve and will take a little more effort to display NetCDF files in the GUI, but allows for nice, 3-d fields.
Antarctica
These are 5km resolution, NetCDF files of Antarctica gathered from various data sources and interpolated, when necessary, onto the same grid using polar stereographic projection.
| Standard Parallel | 71.0 |
| Latitude of Projection Origin | -90.0 |
| False Easting | 0.0 |
| False Northing | 0.0 |
| Straight Vertical Longitude from Pole | 0.0 |
| Lower Left Corner X-Value | -2800 km |
| Lower Left Corner Y-Value | -2800 km |
Antarctica Files
| Antarctica with Ice Shelves | The data files contains the following fields in a NetCDF format: Latitude, Longitude, Mean Annual Surface Temperature (Comiso et al 2000), Ice Thickness from BEDMAP (Liu et al. 1999), Accumulation (Vaughan et al. 1999), Ice Surface Elevation from BEDMAP(Liu et al. 1999),Bed Topogrphy from BEDMAP (Lythe et al 2001), Basal Heat Flux(Shapiro and Ritzwoller 2004), Thickness Mask, and Surface Velocity. | Media:Antarctica_5km_withshelves.nc |
| Antarctica without Ice Shelves | The data files contains the following fields in a NetCDF format: Latitude, Longitude, Mean Annual Surface Temperature (Comiso et al 2000), Ice Thickness from BEDMAP (Liu et al. 1999), Accumulation/Ablation Rate (Vaughan et al. 1999), Ice Surface Elevation from BEDMAP (Liu et al. 1999),Bed Topogrphy from BEDMAP (Lythe et al 2001), Basal Heat Flux (Shapiro and Ritzwoller 2004), Thickness Mask, and Surface Velocity. The fields are adjusted for models that don't handle ice shelves very well and are removed using the attached mask file. | Media:Antarctica_5km_woshelves.nc |
The recent changes to the files above can be found in the change log.
Greenland
These are 5km resolution, NetCDF files of Greenland gathered from various data sources and interpolated, when necessary, onto the same grid using polar stereographic projection.
| Standard Parallel | 71.0 |
| Latitude of Projection Origin | -90.0 |
| False Easting | 0.0 |
| False Northing | 0.0 |
| Straight Vertical Longitude from Pole | -39.0 |
| Lower Left Corner X-Value | -800 km |
| Lower Left Corner Y-Value | -3400 km |
Greenland Files
| Greenland | The data files contains the following fields in a NetCDF format: Latitude, Longitude, Ice Thickness, 5km, corrected,(Bamber 2001), Bed Topography, 5km, corrected,(Bamber 2001), Ice Surface Elevaton, 5km, corrected,(Bamber 2001), Precipitation, mean annual total precip from 1985 to 1999, (David H. Bromwich, Qiu-shi Chen, Le-sheng Bai, Elizabeth N.,Cassano and Yufang Li 2001) | media:Greenland.nc |
The recent changes to the files above can be found in the change log.
Data Fields Table
Anarctica
| Input Field | We use: | Huybrechts uses: | Notes: |
|---|---|---|---|
| Precipitation | Vaughan et al. 1999 J. Climate 12, 933-946 | Giovinetto and Zwally, 2000, used in (Huybrechts et al. 2000) and updated with rates obtained from shallow ice cores during EPICA pre-site surveys (Oerter et al., 1999, 2000; Rotschky et al. 2007). | Better precip fields available?
netCDF, CF 1.0. Polar Stereographic projection, 5 km |
| Bed topography | BEDMAP Lythe et al 2001 | BEDMAP (Lythe et al. 2001) with older datasets for oceanic bathymetry (Huybrechts et al., 2000) to circumvent artifacts in BEDMAP at grounding lines and below ice shelves. | Bathymetry would be nice (how to get?). We are also have U. Texas data on bed topography in Amundsen Sea Embayment
netCDF, CF 1.0. Polar Stereographic projection, 5 km |
| Ice thickness | BEDMAP | BEDMAP | BEDMAP with data from U. Texas inserted for the Amundsen Sea Embayment
netCDF, CF 1.0. Polar Stereographic projection, 5 km |
| Surface Elevation | BEDMAP | BEDMAP | Can get a better data set from RAMP?
netCDF, CF 1.0. Polar Stereographic projection, 5 km |
| Temperature record | Vostok, interpolated over 100 yr intervals | Vostok, in one his latest paper he uses the new EPICA EDC deuterium record for spin-up over the last 740kyr and the EDML Delta 18 O record for the last 170 kyr, given in the paper (Ruth et al., 2007 issue;) | Likely Sufficient
Text file, also in NetCDF |
| Sea Level change | SPECMAP | SPECMAP,
Also a combination of a planktonic Delta 18 O record from the tropical ocean(Bassinot et al., 1994), using only the most recent 21kyr for the incomplete part of the Bassinot record. |
SPECMAP improvements?
Text file, also in NetCDF |
| Mean Annual Temperature | Comiso et al 2000 | Calculated on the first step with lapse rates, surface elevation and latitude? Adjusted by climate model? | netCDF, CF 1.0. Polar Stereographic projection, 5 km |
| Geothermal flux | Shapiro and Ritzwoller 2004 | Uniform | Fox Maule et al. 2005 is likely better |
| Future Precipitation Forcing | |||
| Future Temperature Forcing | |||
| Future Ocean Forcing? |
Greenland
| Input Field | We use: | Huybrechts uses: | Notes: |
|---|---|---|---|
| Precipitation | PARCA model output from 1985 to 1999 | The base map was revised from Ohmura and Reeh(1991) by incorporating the results of shallow ice cores taken in North Greenland(Jung-Rothenhausler, 1998) | netCDF, CF 1.0. Polar Stereographic projection, 5 km |
| Bed topography | Bamber (2001) JGR 106,33781 | Bamber (2001) | netCDF, CF 1.0. Polar Stereographic projection, 5 km |
| Ice thickness | Bamber (2001) | Bamber (2001) | netCDF, CF 1.0. Polar Stereographic projection, 5 km |
| Surface elevation | Bamber (2001) | Bamber (2001) | netCDF, CF 1.0. Polar Stereographic projection, 5 km |
| Temperature time series | GRIP for 125kyr, interpolated over 100 year intervals | GRIP for 100kyr, Vostok for previous | Text file, and now in NetCDF |
| Sea Level Change | SPECMAP | SPECMAP with zero sea level change at 225kyr BP and then forced for 4kyr to present? Done in a phenomenological nature. (Funder, 1989; Funder et al., 1998) | Text file, also in NetCDF |
| Mean Annual Temperature | Parameterized by Reeh(1991) based on data by Ohmura(1987) | Calculated on the first step with lapse rates, surface elevation and latitude? Adjusted by climate model? | netCDF, CF 1.0. Polar Stereographic projection, 5 km |
| Future Precipitation Forcing | |||
| Future Temperature Forcing | |||
| Future Ocean Forcing |
