# Presentation: 846989

## Global Land Surface Memory and Its Impacts 

- <date/time>

- The lower boundary condition of the atmosphere, such as SST, soil moisture and snow cover often have a longer memory than weather itself. Land surface processes play an important role in weather and climate prediction. In order to improve our understanding of land surface-atmosphere interaction on different time scales, we need to improve our understanding of the land surface hydrological & energy cycles. Also to further improve weather forecast & climate prediction, we need more accurate land initial conditions.

** ****Motivation & Background **

**1**

**Land Surface Memory & its impacts**

** ****Summary & Future Work**

- An accurate and homogeneous global lower boundary condition is very important
- for weather and climate predictions.
- The preliminary results show that the CPC global (near real time) soil moisture
- dataset can reasonably reproduce the annual cycle & interannual variability of the
- observed soil moisture, when compared to Illinois observations and GRACE
- satellite data. The simulated land surface hydrologic cycle and extreme events
- also look realistic.
- Future Work
- Need more detailed data validation & analysis. Add a simple cold season physics in near future.
- Model comparisons (e.g. With RR, Noah LSM and VIC LSM etc. ).
- Demonstrate more detailed non-local impacts of soil moisture & prediction experiments etc.
- Reference:
- Fan, Y., H. van den Dool, 2004: Climate Prediction Center global monthly soil moisture data set at 0.5 degree resolution
-      for 1948 to present. *J.Geophys.Res*. 109, D10102, doi:10.1029/2003JD004345
- H. van den Dool, J. Huang, and Y. Fan, 2003: Performance and analysis of the constructed analogue method applied to
-      U.S. soil moisture over 1981-2001. *J. Geophys. Res*., 108(D16), 8617, doi:10.1029/2002JD003114
- Huang, J., H. van den Dool, and K. G. Georgakakos, 1996: Analysis of model-calculated soil moisture over the US (1931-
-      1993) and applications to long range temperature forecasts. *J.Climate*, 9, 1350-1362.
*Also see the poster by Huug van den Dool et al for the latest GRACE data comparisons.*
- Acknowledgment: This project was supported by the GCIP Grant (GC00-095) and GAPP
-                               Grant (GC04-039).

**2**

**5**

**Temporal & spatial evolution**

***Global Land Surface Memory and Its Impacts****** ***
*Yun Fan, Huug van den Dool & Peitao Peng*
*CPC/NCEP/NOAA*

**4**

**6**

- EOFs & PCs of the global lower boundary (normalized SST and soil moisture) for March 1950-2003. Both the El-Nino Southern Oscillation and long term trend modes are clearly seen in the leading EOFs & PCs of combined SST and soil moisture..

**http://www.cpc.ncep.noaa.gov/soilmst/index.htm**

**Model & Data**

- The maximum & minimum land surface soil moisture and the months of these extremes take place.

- Seasonal variation of the land surface water recharge or discharge. Monsoon is the dominant feature.

- Auto correlations of the global land surface soil moisture,which show that cold seasons and dry areas often have longer memory than those in warm seasons and wet areas.

- Non-local correlations of the land surface soil moisture (southeast China or Bengal)  and the global land surface precipitation and air temperature show the non-local impacts of the land surface soil moisture.

- The soil moisture budget (Huang et al 1996) over an area A:
** **Where  W(t) is soil water content                P(t) precipitation          E(t) evapotranspiration
-               R(t) net streamflow divergence     G(t) net groundwater loss
-  Forcing Data:
-        -CPC Monthly Global Precipitation Over Land
-        -Monthly Global Reanalysis/CDAS 2m Temperature
- Data Coverage:    56+ years (1948-present)

***The 29******th****** CDPW, Madison, Wisconsin, Oct. 18-22, 2004***

**3**

**CPC soil moisture monitor & prediction activities**

-  Drought & flood monitoring
-  Empirical forecast tools (Constructed Analog)
-  GFS forecast & climate prediction
***Recent CPC global soil moisture status***

*Simulated extreme hydrological events*

- Difference of March & September soil moisture climatology, which shows two kinds of climates and annual range of land surface soil water variability.

- The annual cycle (right) & anomalies (left) of the observed (black) and simulated (green) top 1 meter column soil moisture in north, central & south Illinois from 1984 to 2004.

- Local correlations of the land surface soil moisture and the land surface air temperature in next month show local impacts of the soil moisture on the land surface air temperature.