# Presentation: 920178

- GODAS initial conditions in the CFS hindcasts
- for 1981 - 1990
- Contributors: Wanqiu Wang, Yan Xue, Jae Schemm,
- 			  Hui Wang

**To investigate the impact of GODAS corrections made for 1981-1990 on the CFS hindcast skill, 15 ensemble member runs are made for each January and July month in 1981-1990 with five atmospheric I.C. paired with each oceanic I.C. centered on Dec. 11, 21, Jan. 1 and June 11, 21, July 1.**
**Impact of GODAS corrections on model’s climatologies and hindcast skill in 1981-2004 is assessed for sea surface temperature, precipitation and 2m temperature. **
**Mean SST is reduced by 0.2-0.4 degree due to GODAS corrections, which reduces warm biases but worsens cold biases, particularly for June IC’s.  Changes in precipitation bias are confined in the Tropics.**
**SST hindcast skill is significantly increased, most prominent in the Pacific and Indian Ocean for December IC’s and in the Atlantic Ocean for June IC’s.**
**Slight increase in skill over the North American Sector for 2m temperature and spring precipitation with corrected GODAS.**

## JFM

- JAS

- AMJ

**Average SST at Equator for 1981-1990**

**June Start**

**Dec Start**

**Standard - Obs**

**newGodas - Standard**

**Standard - Obs**

**newGodas - Standard**

## JFM

- JAS

- AMJ

**Average TAUX at Equator for 1981-1990**

**June Start**

**Dec Start**

**Standard - Obs**

**newGodas - Standard**

**Standard - Obs**

**newGodas - Standard**

## SST indices from the web site of Ocean Observations Panel for Climate (OOPC)

**SST indices from the web site of Ocean Observations Panel for Climate (OOPC)**

## JAS

- JFM

- OND

**SST Indices Hindcast Skill in 1981-2005 (****red ******** improvement****)**

## SST hindcast averaged in the hurricane main development region (MDR) for July-November starting from June 11-31 I.C.. The SST hindcast is reduced (green) in 1981-1990 and increased (red) in 1991-2005 due to GODAS corrections. CFS realistically simulated the peaks of the index in 1987, 1995, 1998 and 2003-2005, and valleys in 1984-1986 and 1994, which suggests a potential contribution of the CFS forecast for the hurricane outlook.

**SST hindcast averaged in the hurricane main development region (MDR) for July-November starting from June 11-31 I.C.. The SST hindcast is reduced (green) in 1981-1990 and increased (red) in 1991-2005 due to GODAS corrections. CFS realistically simulated the peaks of the index in 1987, 1995, 1998 and 2003-2005, and valleys in 1984-1986 and 1994, which ****suggests a potential contribution of the CFS forecast for the hurricane outlook****.**

## Slide 8

## North America

## Slide 10

## Summary

**Continue to investigate the impact of GODAS corrections on atmospheric circulation and subsurface ocean temperature with December and June runs.**
**The two test cases clearly demonstrate that the GODAS corrections have  significant positive impact on tropical SST prediction,  and also positive impact on U.S. precipitation and 2m temperature. **
**CST’s approval is requested at this time for the extension of hindcast reruns for April and October ICs****. These cases will be used to evaluate impact on the hurricane and winter season predictions.**