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项目总结会个人提交演示文稿模板

VIEWS: 6 PAGES: 25

									        Cryospheric Data Assimilation
An Integrated Approach for Generating
      Consistent Cryosphere Data Set

                                    Xin Li
          World Data Center for Glaciology and Geocryology at Lanzhou
 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese
                              Academy of Sciences




                                   CODATA 2006                                     1
                             October 23-25, 2006, Beijing
   Land data assimilation in WDCGG
• Establishing an integrated data and information service is one of
  the major objectives of the International Polar Year (IPY). The
  land data assimilation technology, which was booming in the
  last few years, provide an integrated approach to generate
  spatial and temporal consistent datasets of snow, frozen soil and
  other cryospheric (and related land surface) states. We have
  developed a land data assimilation system which can assimilate
  remote sensing observations into land surface models and then
  produce reanalyzed cryospheric datasets with high spatial and
  temporal resolutions.

                                                                      3
 Chinese Land Data Assimilation System

• The objective of CLDAS is to develop an
  operational Land Data Assimilation System for
  the whole China’s land territory with a spatial
  resolution of 0.25 and temporal resolution of
  one hour, and in the mean time to improve the
  presentations of cold region process in both land
  surface models and radiative transfer models.


                                                      4
         1. Overview of CLDAS

                    Observation operator
                    Radiative transfer model


                                                 Data Assimilation
  Data                                           • EnKF
•Forcing
•Parameters            LDAS                      • 4DVA
                                                 • Partical filter
•Observations                                    • VFSA



                      Model operator
                      Land surface model
                Distributed hydrological model



                                                                     5
LDAS -- (1) Ensemble Prediction




     CoLM


                 Ensemble prediction
……


  N ( X b , B)
LDAS -- (2) Ensemble Kalman filter




                         SSM/I            AMSR-E
                                      +

       Kalman gain   ×   Innovation
                           vector
 2. Forcing data preparation by using an
  atmospheric data assimilation system

• In CLDAS, the forcing data are prepared by an
  atmospheric data assimilation system based on
  Newtonian nudging. The NCEP reanalysis data are
  dynamically downscaled using the regional climatic
  model MM5 with reanalysis data as the background
  and observations. Comparisons with the objective
  analysis of meteorological measurements and the
  uncontrolled modeling showed that the atmospheric
  data assimilation system can produce more reliable
  downscaling of forcing fields.
FDDA - objective analysis   MM5 - objective analysis
500 hPa wind speed (U)      500 hPa wind speed (U)
FDDA - objective analysis   MM5 - objective analysis
surface temperature         surface temperature
            Dynamically downscaled forcing data of July, 2002



Precipitation                                              Air
                                                           temperature




 Humidity                                                  Downward
                                                           shortwave
                                                           radiation
       3 Land models in CLDAS

• Common land model

• SiB2 with frozen soil
  parameterization

• JMA new SiB




                                12
                                                                             Frozen soil parameterization in SiB2
                                                                    0.60                                                                                                                                                      0.00

                                                                                                                                                                                         (a)                                  0.20                          • Comparisons of the
Volumetric liquid water content




                                                                    0.50
                                                                                                                                                                                                                              0.40
                                                                                                                                                                                                                                                              observations and model




                                                                                                                                                                                                                                       Pricipitation (mm)
                                                                                                                                                                                                                              0.60
                                                                    0.40               1: observation of soil moisture at 4cm
                                                                                       2: simulation result in the surface layer with frozen soil parameterization
                                                                                                                                                                                                                              0.80                            simulation results of soil
                                                                    0.30               3: simulation result in the surface layer without frozen soil parameterization                                                     1.00
                                                                                                                                                                                                                              1.20                            moisture in (a) the surface layer,
                                                                    0.20
                                                                                                                                                                                                                              1.40
                                                                                                                                                                                                                              1.60
                                                                                                                                                                                                                                                              (b) the root zone, and (c) the
                                                                    0.10
                                                                                                                                                                                                                              1.80                            deep soil at MS3608 site,
                                                                    0.00                                                                                                                                                  2.00
                                                                           9/1/97        9/29/97               10/27/97               11/24/97               12/22/97             1/19/98                                                                     Tibetan Plateau from Sep 01,
                                                                                                                                  Time
                                                                                                                                                                                                                                                              1997 to Jan 31, 1998

                                                                                                                                                                                     Volumetric liquid water content
                                                                                        1: observation of soil moisture at 4cm
                                                                                                                                                                                                                       0.40
                                                                                        2: observation of soil moisture at 20cm
                                  Volumetric liquid water content




                                                                       0.40             3: simulation result in the root zone with frozen soil parameterization                                                                                                                                                                               (c)
                                                                                        4: simulation result in the root zone without frozen soil parameterization          (b)                                        0.30
                                                                       0.30

                                                                                                                                                                                                                       0.20
                                                                       0.20

                                                                                                                                                                                                                       0.10                                  1: observation of soil moisture at 100cm
                                                                       0.10
                                                                                                                                                                                                                                                             2: simulation result in the deep soil with frozen soil parameterization
                                                                                                                                                                                                                                                             3: simulation result in the deep soil without frozen soil parameterization
                                                                       0.00                                                                                                                                            0.00

                                                                              9/1/97      9/29/97            10/27/97             11/24/97           12/22/97           1/19/98                                               9/1/97                           9/29/97            10/27/97              11/24/97           12/22/97       1/19/98
                                                                                                                              Time                                                                                                                                                                 Time
                            JMA new SiB




•   JMA-GSM currently adopts a Simple
    Biosphere (SiB) model, which is
    developed by Sellers in 1986.
•   In new SiB, snow and soil processes
    are improved substantially.
4. Passive microwave remote sensing
    of snow and soil freeze/thaw
 Snow depth data set (1978-2005) derived
         from PM remote sensing




                                           Mean snow depth (1978-2005)
    Daily snow depth of 2001




Snow depth variation from 1978 to 2005   Monthly maximum snow depth
                     Monitoring of surface freeze/thaw
          45
                                                                             2001年全国冻结天数
          40


          35


          30
                           frozen
                           Thaw
                           Desert
                                                                                                        Legend
19V-19H




                                                                                                        fday
          25


          20




                                                                                                        Value
          15


          10


          5
               140   160   180      200   220
                                          37V
                                                240   260   280   300
                                                                                                                 365
                                                                                                                     High :
                 Classification of frozen or thawed soil

                                                                                                                     Low :
                                                                                                                 1
                                                                              Maximum frozen days in 2001


                                                                             Daily surface freeze/thaw in 2001


                                                                        Frozen
                                                                        Thaw
                                                                        Desert
                                                                        Precipitation
5. CLDAS Validation and output
                                   Point experiment of assimilating TMI and
                                                AMSR-E data
Deep
layer




                                                                                                                                                                         Volumetric water content (m3 m-3)
                                                                                                                                                                                                             0.4
                                                                                                                                                                                                                                                                                                                               Assimilation
                                                                                                                                                                                                                                                                                                                               Observation
                                                                                                                                                                                                             0.3

 Root
                                                                                                                                                                                                             0.2
 zone
                                                                                                                                                                                                             0.1


                                                                                                                                                                                                             0.0

                                                                                                                                                                                                             2003-01-01                      2003-03-02        2003-05-01   2003-06-30                  2003-08-29        2003-10-28   2003-12-27
Surface                                                                                                                                                                                                                                                                              Time

layer
                                                                                                                                                                                                     Model operator: JMASiB; Observation operator: Q/h model;
                                                                                                                                                                                                       Assimilation time: 2003/1/1-/12/31; Data: CEOP Tibet
                                                                                                                                                                                                                             reference
         Model operator: SiB2; Observation operator: AIEM;
        Assimilation time: 1998/7/6-1998/8/9; Data: GAME-Tibet
                                MS3608

                          310.0
                                          A3                                    310.0
                                                                                               C2                                     310.0
                                                                                                                                                    E4                                                                           310.0
                                                                                                                                                                                                                                               G6                                           310.0
                                                                                                                                                                                                                                                                                                          H7
                          300.0                                                 300.0                                                 300.0                                                                                      300.0                                                      300.0




                                                                                                                                                                                                                                                                              Observation
            Observation




                                                                                                                        Observation




                                                                                                                                                                                                                   Observation
                                                                  Observation




                          290.0                                                 290.0                                                 290.0                                                                                      290.0                                                      290.0


                          280.0                                                 280.0                                                 280.0                                                                                      280.0                                                      280.0


                          270.0                                                 270.0                                                 270.0                                                                                      270.0                                                      270.0

                                  270.0 280.0 290.0 300.0 310.0                         270.0 280.0 290.0 300.0 310.0                         270.0 280.0 290.0 300.0 310.0                                                              270.0 280.0 290.0 300.0 310.0                              270.0 280.0 290.0 300.0 310.0
                                           Estimation                                            Estimation                                            Estimation                                                                                 Estimation                                                 Estimation




                             Model operator: JMASiB; Observation operator: Q/h model; Assimilation time:
                             2003/5/1-/9/30; Data: CEOP Mongolia reference
                       Point experiment of assimilating AMSR-E data
                                 for snow state estimation

             • Data: CEOP Siberia reference; Land
               model: CoLM; Radiative transfer model
               of snow: MEMLS

            1.0                                                         0.0                                  300

                                                                                                                         积雪层平均温度
                                                                                 -4
                                                                        1.0x10
            0.8              地面自动观测                                                                          280
                             CLM单独模拟                                             -4
                             积雪数据同化系统                                   2.0x10
                                                                                 降水率( mm/s)




            0.6                                                                                              260
雪深( m)




                                                                                 -4
                                                                                              温度( K)




                                                                        3.0x10


            0.4                                                         4.0x10
                                                                                 -4
                                                                                                             240                                                                          0.4




                                                                                                                                                                        积雪数据同化系统输出雪深(m)
                                                                        5.0x10
                                                                                 -4
                                                                                                                                                                                                          y = 0.9307x
                                                                                                                                                                                                          R2 = 0.7106
            0.2                                                                                              220
                                                                                 -4
                                                                        6.0x10
                                                                                                                                                                                          0.3
            0.0                                                                                              200
            2003-9-1     2003-11-1   2004-1-1     2004-3-1   2004-5-1                                        2003-9-1    2003-11-1   2004-1-1     2004-3-1   2004-5-1
                                           (a)                                                                                              (b)
            15
                       积雪层平均液态水含量                                                                            0.8
                                                                                                                        积雪层平均密度                                                           0.2
            12
                                                                                                             0.6
 液态水含量(%)




             9                                                                                                                                                                            0.1
                                                                                                密度( g*cm3)




                                                                                                             0.4

             6



             3
                                                                                                             0.2
                                                                                                                                                                                            0
                                                                                                                                                                                                0   0.1        0.2      0.3   0.4
                                                                                                             0.0
              0
            2003-9-1     2003-11-1   2004-1-1     2004-3-1   2004-5-1                                        2003-9-1    2003-11-1   2004-1-1     2004-3-1   2004-5-1
                                                                                                                                                                                                          地面观测雪深(m)
                                            (c)                                                                                            (d)                                                               (b)
     Assimilated dataset for west China (July, 2002)



Volumetric                                      Volumetric
LWC in                                          ice content
surface layer                                   in surface
                                                layer




Soil                                            Snow depth
temperature
in surface
layer
      Assimilated dataset for west China (July, 2002)



Volumetric                                       Volumetric
LWC at                                           LWC at
second layer                                     third layer




Soil                                            Soil
temperature at                                  temperature at
second layer                                    third layer
   Assimilated dataset for west China (July, 2002)



Sensitive                                     Latent
heat flux                                     heat flux




Ground                                        Evapotran
heat flux                                     sipiration
                 6. Summary
• We have developed a LDAS for China’s land territory.
  By merging the remote sensing observations into the
  dynamics of land surface model, CLDAS is capable of
  producing the evolution of land surface states, such as
  soil moisture, soil temperature and snow water
  equivalent, in good physical and spatiotemporal
  consistence and improved accuracy.
• CLDAS is capable of using passive microwave remotely
  sensed data such as SSM/I, TMI, and AMSR-E. We
  expect that the CLDAS output will be used in various
  large-scale and catchmental-scale land surface and
  hydrological studies and can have a potential
  contribution to IPY.
 ldas.westgis.ac.cn
wdcdgg.westgis.ac.cn




                       25

								
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