Development of Bias-Corrected Precipitation Database and

Document Sample
Development of Bias-Corrected Precipitation Database and Powered By Docstoc
					 Development of Bias-Corrected
   Precipitation Database and
Climatology for the Arctic Regions
      Daqing Yang, Principal Investigator
       Douglas L. Kane, Co-Investigator
        Institute of Northern Engineering
         University of Alaska Fairbanks

       David R. Legates, Co-Investigator
         Center for Climatic Research
           Department of Geography
            University of Delaware
              Outline

• Background /Goals
• Methods
  - Results and applications of WMO
  gauge intercomparison project
• Data Sources
• Major Tasks
• Results/Products/Impacts
    Uncertainties of Precipitation Records and
        Climatology in the Arctic regions

• Sparseness of the precipitation observation networks;

• Uneven distribution of measurement sites, i.e. biased
  toward coastal and the low-elevation areas;

• Spatial and temporal discontinuities of precipitation
  measurements induced by changes in observation
  methods and by different observation techniques used
  across national borders; and
• Biases of gauge measurements, such as wind-induced
  undercatch, wetting and evaporation losses, and
  underestimate of trace amount of precipitation.
                Research Goals

• Evaluate and define the accuracy of precipitation
  measurements in the Arctic regions.
• Implement the consistent bias-correction methods
  over the pan-Arctic, i.e. Alaska, northern Canada,
  Siberia, northern Europe, Greenland, and the
  Arctic Ocean.

• Develop biased-corrected and compatible
  precipitation database (including grid products)
  and climatology for the Arctic regions as a whole.
US Wyoming snow system in Barrow, AK   WMO double fence intercomparison reference (DFIR)
                                       in Barrow, AK
                                                              Canadian Nipher       NWS 8" Alter
                                   120
                                                              NWS 8" unsh           Hellmann unsh
Ratio of gauge catch to the DFIR

                                                              Tretyakov
                                   100


                                   80
              (%)




                                   60


                                   40


                                   20


                                    0
                                         0   1   2        3      4       5      6       7     8     9

                                                     Wind speed at gauge height (m/s)
                                                                                                                                                       Annual precipitation (mm)
                                                                                                                        Ca
                               Annual precipitation (mm)                                                                    p




                                                                                                                                                100
                                                                                                                                                      200
                                                                                                                                                            300
                                                                                                                                                                  400
                                                                                                                                                                        500
                                                                                                                                                                              600
                                                                                                                                                                                    700
                                                                                                                                                                                                800
                                                                                                                                                                                                           900




                                                                                                                                            0
                                                                                                                     Cl e P
                                                                                                                        in
                                                                                                                           to arry
                                                                                                                              n
                                                                                                                        Co Po
                                                                                                                            p in
19                                                                                                                   Fo pe t




                    100
                                 150
                                       200
                                             250
                                                   300
                                                         350
                                                               400
                                                                     450
                                                                           500




          0
              50
                                                                                                                        rt rni
     48                                                                                                                              n
                                                                                                                    Fo Rel e
19                                                                                                                      rt ian
                                                                                                                           Si c e
     50                                                                                                                        m
19                                                                                                                      Fo ps
                                                                                                                             rt on
     52                                                                                                                          S
19                                                                                                                        Na mit
     54                                                                                                                        y h
                                                                                                                                  Ri
                                                                                                                                     ve
19                                                                                                                  No                  r
     56                                                                                                                rm In
                                                                                                                           an vik
19
     58                                                                                                         Ee Y W e
                                                                                                                  llo ello lls
19                                                                                                                   wk w
                                                                                                                          ni kni
     60                                                                                                                     fe        fe
19                                                                                                                     Ba Hy
     62                                                                                                             Co r    ke dro
19                                                                                                                      ra La
     64                                                                                                                    l H ke
                                                                                                                                ar
19                                                                                                                        Pe bou
     66                                                                                                                        lly r
                                                                                                                 Br                Ba
19                                                                                                                 ou                  y
     68                                                                                                               gh          A




                   archived
                                                                                                                          to ler
19                                                                                                                           n         t
     70                                                                                                                 Ca Isla
19                                                                                                                   Ca      pe nd
     72                                                                                                                  pe Dy
                                                                                                                              Ho er
19                                                                                                                                 op
     74                                                                                                                               e
                                                                                                                     De C r
19                                                                                                                       wa lyd
     76                                                                                                                       rL e
                                                                                                                                  ak
19                                                                                                                                   e
     78                                                                                                                       Eu s
                                                                                                                        Ha re
19                                                                                                                          ll k e
     80                                                                                                                         Be
                                                                                 Whitehorse, Yukon, 1948-1994




                                                                                                                                    ac
19                                                                                                                  Lo                 h
     82                                                                                                               ng Iqa
                                                                                                                           st lui


                   corrected
19                                                                                                                    M       af t
     84                                                                                                                  ao f Bl
                                                                                                                             ka uff
19                                                                                                                               rI
     86                                                                                                                    Re nle
                                                                                                                                so t
19                                                                                                                      B
                                                                                                                                                                                                                 Summary of bias correction in NWT, Canada, 1961-1990




     88                                                                                                           Ca yro lute
                                                                                                                      m n
19                                                                                                                       br Ba
                                                                                                                           id
     90                                                                                                                        g y
19                                                                                                                      M eB
                                                                                                                   Sa ou ay
                                                                                                                                                                                    corrected
                                                                                                                                                                                                measured




     92                                                                                                               c h ld
19                                                                                                                        s Ba
                                                                                                                             Ha y
     94                                                                                                                           rb
                                                                                                                                    ou
                                                                                                                                        r
                                    35
                                                      trace

                                    30                wind-loss

                                                      measured
                                                                                                             Overall mean
                                    25                                                                       for the NP
               Precipitation (mm)



                                    20                                                                       drifting stations,
                                    15                                                                       1957-90 (Yang,
                                    10                                                                       1999)
                                    5

                                    0
                                         1   2    3       4       5      6     7     8   9   10   11   12
                                                                      Months


                                    80

                                    70
                                             trace amount
                                                                                                             Overall mean
                                             wind correction
                                                                                                             for 61 climate
Precipitation (mm)




                                    60
                                             measured
                                    50

                                    40
                                                                                                             stations in
                                    30                                                                       Siberia, 1986-
                                    20
                                                                                                             92 (Yang and
                                    10

                                     0
                                                                                                             Ohata, 2001)
                                         1   2     3          4   5       6      7   8   9   10   11    12

                                                                         Month
                                             Comparison of Bias Corrections in the High Latitudes
                                    3.00
Range of yearly correction factor




                                    2.50




                                    2.00




                                    1.50




                                    1.00




                                    0.50
                                           Siberia     Alaska       NWT        Greenland   Arctic basin

                                                                 Regions
                                                                    a) DIKSON, 73.30N, 80.24E                 trace amount
                                                      120
                         Monthly precipitation (mm)
                                                                                                              wind loss
                                                      100
                                                                                                              measured
                                                      80

                                                      60
                                                      40

                                                      20

                                                       0
                                                                1       2   3       4        5       6        7      8       9    10    11        12



                                                            a) Dikson (73.30N, 80.24E)
Daily snow fall precipitation




                                                       35
                                                       30
                                                       25
                                                       20
           (mm)




                                                       15
                                                       10
                                                        5
                                                        0
                                                            0       2       4           6        8       10        12        14    16        18        20
                                                                                        Daily mean w ind speed at 2m (m/s)
                   Data Sources
Daily precipitation, temperature and wind speed are needed
  for this research.
• National Climatic Data Center (NCDC), global daily
  surface data archive (1994-present) for over 8,000
  stations around the world,
  http://www.ncdc.noaa.gov/cgi-bin/res40.pl
• WMO GTS, the Global Climate Observing System
  (GCOS) Surface Network (GSN),
  http://www.wmo.ch/web/gcos/gcoshome.htlm
• Arctic Precipitation Data Archive (APDA) at the Global
  Precipitation Data Center (GPDC),
  http://www.dwd.de/research/gpcc/acsys
• Arctic Ocean (6 hourly and daily) met data
  collected at the Russian NP drifting station,
  National Snow and Ice Data Center (NSIDC)
  http://www-nsidc.colorado.edu/index.html

Station and gauge info:
  – type of precipitation gauge
  – height of gauge and wind sensor
  – wind shield
WMO and national weather services:
  – USA, Canada
  – Russia, Finland, Denmark, ...
Synoptic/climate stations on land above 45N and the Arctic
   Ocean drifting stations will be used for this research




                Canada


                                                   Mongolia
                                                              China


                                          Russia




                         Greenland
                                               Kazakhstan
                Major Task 1:
  Evaluation and Implementation of the WMO
Bias Correction Methods - threshold wind 6.5m/s

• Analysis of wind regimes over the arctic regions
• Focus on winter season and on snowfall days

• Define regions where the WMO bias correction
  methods may not be appropriate and therefore
  alternative approaches or further experimental
  studies should be considered
                   Major Task 2:
       Development of Bias-Corrected Arctic
      Precipitation Database and Climatology

• Implement the WMO methods to all the stations in the
  Arctic regions for last 30 years, 1970-2000???

• Create bias-corrected daily precipitation dataset- an
  important basis for analyses of Arctic regional
  precipitation, i.e. long-term mean, seasonal cycle, year-
  to-year variation, and trend
• Develop improved precipitation climatology for the Arctic
  regions
   –Consider terrain and the orographic effect on precipitation
    distribution, use high-resolution digital elevation models (DEM)
    to determine elevation, slope, and aspect of the topography
   –Apply PRISM (Daly et al., 1994) and the High-Resolution
    Weather Data System (HRWxDS) (Legates et al,. 1999) to
    generate regional maps of monthly/yearly bias-corrected
    precipitation
   –Develop gridded precipitation data, use equal-area EASE grid
    system, compatible with ACSYS/Arctic Precipitation Data
    Archive (APDA), hydrological model intercomparison project,
    and RS snowcover (SCE/SWE) products
                  Major Task 3:
      Comparison and Validation of the Results
• Compare our results with other precipitation
  datasets/products, such as Legates and Willmott (1990),
  Jaeger (1983), UNESCO (1978), Adam and Lettenmaier
  (2003), and others?
• Compare gauge measurements/corrections with snowcover
  accumulation in selected regions/basins
• Assess the impact of precipitation bias corrections to regional
  hydrologic model analyses (Zhang et al., 2000)
• Compare GCM/RCM precipitation simulation with the
  observed and bias-corrected precipitation fields in selected
  regions, i.e. Alaska and central Siberia
   – model simulation agrees better to bias-corrected precipitation
     fields particularly in winter months and over windy areas !?
            Results/Products/Impacts
• Practical procedures for correcting gauge-measured
  precipitation data in the high latitude regions
• Bias-corrected daily/monthly/yearly (station)
  precipitation records/correction factors (CF, %) for arctic
  regions across national boundaries
• Bias-corrected, gridded monthly/yearly regional
  precipitation data/climatology for the arctic regions
• Impacts:
   – water balance calculations of both the Arctic Ocean and
     terrestrial systems
   – climate change analysis and hydrologic modeling
   – validation of GCM/RCM simulations
   – calibration of remote sensing data/products

				
DOCUMENT INFO
Shared By:
Stats:
views:10
posted:2/11/2009
language:English
pages:18