North American Regional Climate Change Assessment Program

Transcription

1 North American Regional Climate Change Assessment Program Toni Rosati IMAGe NCAR

2 Outline Basic concepts of numerical climate modeling NetCDF data format overview NARCCAP project NARCCAP curation and citation

3 The fundamental element of climate simulation is a big box of air 200 x 200 GCM 50 x 50 km in NARCCAP

4 Each box is represented by 6 numbers hus: humidity ps: pressure ta: temperature ua: E-W wind va: N-S wind zg: height Simulation: apply Partial Differential Equations for fluid flow to each box to update the 6 numbers and calculate flux between neighboring boxes. ( dynamical core )

5 Sub-models for other processes ( physics ) radiation transfer land surface planetary boundary layer convection microphysics (rain/clouds) Sub-gridscale processes are handled by parameterization (e.g., thunderstorms)

6 Climate models represent reality as big grids of numbers ( Raster data in GIS parlance)

7 How do you store the data? Binary: platform dependent, opaque Plain text: huge files, format ambiguity ?

8 NetCDF Network Common Data Form self-describing platform-independent array-oriented scientific data file format

9 NetCDF Data Model lat orog //GLOBAL title: island topography creator: Seth McGinnis Conventions: CF lat units: km missing_value: units: degrees_north lon lon units: degrees_east

10 Variables lat orog //GLOBAL title: island topography creator: Seth McGinnis Conventions: CF lat units: km missing_value: units: degrees_north lon lon units: degrees_east

11 Dimensions lat orog //GLOBAL title: island topography creator: Seth McGinnis Conventions: CF lat units: km missing_value: units: degrees_north lon lon units: degrees_east

12 Attributes lat orog //GLOBAL title: island topography creator: Seth McGinnis Conventions: CF lat units: km missing_value: units: degrees_north lon lon units: degrees_east

13 File Structure Header defines contents, holds metadata; actual data comes after in body of file ncdump h file.nc NetCDF: binary. Plain-text equivalent: CDL ncdump converts netcdf to CDL ncgen converts CDL to netcdf

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16 CF Metadata Standard CF = Climate and Forecast Set of rules about file naming conventions and metadata contents Designed to promote the processing and sharing of files created with the NetCDF API. Allows smart tools, GIS compatibility standard_name, units attributes NARCCAP data follows v 1.0 CF spec is extensive

17 CF Metadata Standard CF = Climate and Forecast

18 NARCCAP: North American Regional Climate Change Assessment Program Nest high-res* regional models (RCMs) inside coarser global models (GCMs) over N. America *50 km gridcells

19 Goals of NARCCAP Evaluate model performance and uncertainty Generate high-res climate change scenario data for impacts analysis Support further dynamical downscaling experiments

20 6 RCM Modeling Teams CRCM - S. Biner, OURANOS ECP2 - A. Nunes, Scripps HRM3 - R. Jones, et al, Hadley Centre MM5I - B. Gutowski, R. Arritt, ISU RCM3 - M. Snyder, UC Santa Cruz WRFG - R. Leung, PNNL Details: narccap.ucar.edu/data/rcm-characteristics.html

21 Advantages of higher resolution North America at typical global climate model resolution Hadley Centre AOGCM (HadCM3), 2.5 (lat) x 3.75 (lon), ~ 280 km North America at 50 km grid spacing

22 The Basic Idea Nest RCMs inside GCMs to obtain dynamically downscaled data Two 30-year runs, current ( ) and future ( ). SRES A2 emissions scenario for future run narccap.ucar.edu/about/aogcms.html

23 AOGCM-RCM Matrix AOGCMS GFDL CGCM3 HADCM3 CCSM3 MM5 X X** RegCM X** X** RCMs CRCM X** X** HadRM X** X** RSM X** X WRF X** X** *CAM3 *GFDL X** X *= time slice experiments Red = run completed ** = data loaded

24 Looking Into the Future No crystal balls Scenarios, not forecasts Look at current and future No best model Look at multiple models Embrace uncertainty

25 Data Archive Data distribution: earthsystemgrid.org Organization: RCM Driver Table 1 variable per file, 5 years per file* * (except at beginning of run) Filenames: Var_Model_Driver_Time.nc Time = yyyymmddhh of first timestep

26 Data Tables Table 1: daily values (e.g. Tmin & Tmax) Table 2: big 7 variables for impacts: temp, prec, pressure, wind, sun, humidity Table 3: all the other 2-D variables Table 4: static (unchanging) variables Not on ESG! narccap.ucar.edu/data/table4 Table 5: all 3-D variables

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28 NARCCAP Users Three main types of NARCCAP users: Those who want to perform analyses on the NARCCAP output (e.g., for a particular subdomain). Those who want to use the results as climate scenarios for performing impacts studies (e.g. on agriculture, water resources). Those who want to use the results for performing further downscaling experiments, either via higher resolution RCM simulations or statistical downscaling.

29 Analysis Users Comparisons Between models Change between current and future Bias We will use NARCCAP precipitation and temperature data to check the outputs of different coupled combinations between global and regional models to try to answer the question: Among all combinations, which coupled models are perform best throughout the southern U.S and northern Mexico? "

30 Impacts Users Ecology, biology, adaptation, water management Plug into other models Data from these climate change models or scenarios will be used as inputs to the SWAT model to forecast the impacts on water quantity and quality as well as crop and timber yields. We also will examine the likely changes in the ecosystem services based on forecasts of land use change in the region.

31 Further Downscaling Users Statistical Dynamical (WRF) Uncertainty NARCCAP output serves as boundary conditions with which to drive inner nests of the WRF modelled, centered over southern Ontario. This allows climate simulations to be dynamically downscaled over the region of interest

32 The Other Category I'm working on a regional downscaling effort at Oregon State University using RegCM3. I am having trouble formatting our NetCDF output to be CF-1.0 compliant so that it properly imports into ArcGIS. I would like access to the NARCCAP output so I can have a working datasets to compare to. I think we'd benefit by being able to compare our 50km North America runs to those on NARCCAP.

33 Citation First NCAR dataset to receive a DOI Why one DOI? Challenge of finding NARCCAP papers register, but once gotten can t track w/o citations.

34 Curation Different types of users have different support needs Publishing data is different than publishing an article More than just versioning How to make data citation standard practice?

35 Citation Previously, we requested an acknowledgement "We wish to thank the North American Regional Climate Change Assessment Program (NARCCAP) for providing the data used in this paper. NARCCAP is funded by the National Science Foundation (NSF), the U.S. Department of Energy (DoE), the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Environmental Protection Agency Office of Research and Development (EPA)."

36 Citation Mearns, L.O., et al., 2007, updated The North American Regional Climate Change Assessment Program dataset, National Center for Atmospheric Research Earth System Grid data portal, Boulder, CO. Data downloaded [doi: /d6rn35st]

37 [doi: /d6rn35st]