# Presentation: 067656

## Preliminary Results from CaRD10(California Reanalysis Downscaling at 10km) 

- Masao Kanamitsu
- and
- Hideki Kanamaru
-  (Scripps Institution of Oceanography)
**This work is funded jointly by PIER/NOAA/NSF/ESC**

## Objective

**Reconstruction** of the **high-spatial resolution /high-temporal scale** **analysis** of **atmosphere **and** land** covering the **state of California**, neighboring states and ocean **for global change study.**
**Longest possible analysis**
**Highest possible resolution**

## Methodology

**Dynamical downscaling**
**Using a complex atmospheric model to interpolate large scale analysis to regional space and time scale.**
**Advantage**
**The fields obtained are dynamically, thermodynamically and hydrologically consistent (difficult for statistical technique).**
**Can be used to “understand” the dynamics and physics.**
**Disadvantage**
**Model dependent.  Accuracy uncertain.  ********Importance of validation.**

## Model and Data

- Scripps Experimental Climate Prediction Center Hydrostatic Global to Regional Spectral Model (G-RSM).
-  _**Highest possible spatial resolution of  ~10km**_**.**
- NCEP/NCAR Global Reanalysis as a large-scale forcing.
-  _**Only analysis that goes back to 1948**_**.**
- Apply _**Scale Selective Bias Correction**_ technique to preserve the large-scale forcing field within the domain.
_**No other observations**_, except SST, are used.
- Does not incorporate change in land use.
- Responses due to changes in large scale atmospheric circulation and SST.
- Hourly output.

## Two Experimental Phases

- _Two Experimental Phases_

**1. CaRD10**
**	****Jan. 1948-Aug. 2005 Completed!**
- 	Ran on NCAR and multiple national super computing center machines.

**2. Extended North American region**.
**In progress**
- 	Running on Earth Simulator machine in Yokohama, Japan.  To be completed by 2006.

## Challenges

- Computations – *solved*
- Validations and Diagnostics – *this presentation*
- Sensitivity tests – *in progress*
- Improvements – *future work*

## Validation Examples - Coastal Areas

## Hourly Buoy Wind Speed

**Red: CaRD10**
**Black: Buoy**

## Daily Mean Buoy Wind Speed

- Buoy #2-b42

**Red: CaRD10**
**Black: Buoy**

## Catalina Eddy

**CaRD10**

**Mesoscale **
**    ****data **
**assimilation**

- Thompson et al, 1997

**116.5W**

**121W**

**31.5N**

**36.0N**

## Comparisons with NARR

## July 10m Wind Diurnal Variation

**CaRD10**

**NARR**

## July 2m Temp Diurnal Variation

**CaRD10**

**NARR**

## Comparisons with Monthly Mean Station Observations

## Correlation of January Monthly Mean 2m T 

- Correlation of January Monthly Mean 2m T

## Selected Stations

## Seasonal change of correlation of 

- monthly mean 2m T

## Correlation of January Monthly Mean Precip

## Seasonal Change of Correlation of 

- Monthly Mean Precipitation

## Validation of Long Term Trend

## Decadal Variationin Seasonal Change of Precipitation

**Red: 1975-99**
**Black: 1950-74**

**Coast**

**Valley**

**Mountain**

## January 2mT trend comparison (°K/Year)(Obs. 1950-1996, CaRD10 1950-1999)

|  | Station ID | January |  |
| --- | --- | --- | --- |
|  |  | Observation  | CaRD10 |
| Coast | 14 | +0.04 | +0.02  |
|  | 44 | +0.05 | +0.02 |
|  | 32 | +0.04  | +0.02 |
| Valley | 34 | +0.04 | +0.01 |
|  | 27 | +0.02  | +0.00  |
|  | 11 | +0.00  | -0.00  |
|  | 17 | +0.03 | +0.01 |
|  | 18 | +0.01 | -0.00  |
|  | 52 | +0.01  | -0.00  |
|  Mountain | 23 | +0.03  | +0.05  |
|  | 47 | +0.05 | +0.00  |

## January T2m (1975-99)-(1950-74)

## Diurnal Cycle of January T2m 

- Diurnal Cycle of January T2m

**Green: 1975-99**
**Black: 1950-74**

## Inter-annual Variability of January Monthly Mean Wind

**Inter-annual Variability of ****January Monthly Mean Wind**

## Slide 26

## Conclusions

- California region downscaling is complete for 1948-present (Aug. 2005).
- The quality of the downscaled analysis is very promising.
- Excellent in winter
- Reasonable in summer but not quite good  for some variables over some regions.
- The downscaled analysis is useful for global change research and applications.
- Further validation of analysis is necessary.