# Presentation: 441286

## Comparison of RUC Cloud Analyses and Forecasts with Satellite-derived Cloud Properties

- _Bill Smith_, Patrick Minnis
*NASA LaRC*
- Stan Benjamin, Steve Weygandt
*NOAA/ESRL/GSD/AMD*

## Outline

- Recent satellite validation (GOES Cloud height, water path)
- Statistical Comparisons (several months)
- Cloud Amount
- Cloud Height
- Cloud Thickness
- Cloud Water Path
- Summary

- Goal:  Perform statistical comparison between RUC and LaRC satellite-derived cloud properties to help guide the assimilation of satellite cloud parameters and provide baseline for future model evaluations.

## Satellite Data

- NASA LaRC Real-Time 8-km CONUS cloud products derived from GOES-E and GOES-W (Cloud top phase, height, water path)
- CLOUDSAT cloud water path
- NOAA NESDIS Operational Cloud top Height Product (CO2-slicing)

## RUC Data

- Dataset 1 (4 months):
-  Feb 12 - Apr 27, 2007; May 10 - July 4, 2007
-  Analyses, 1-hr, 3-hr and 6-hr forecasts valid at 18 UTC
-  Obtained to test Model analyses and forecasts with GOES
- Note:  Jan 8, 2008 RUC crisis change implemented for improved cloud/vis assimilation.
- Dataset 2 (55 days):
-  March 17 - May 28, 2008 (18, 19, 20, 21, 22 UTC Analyses)
-  No Forecasts
-  Obtained for GOES and Cloudsat Comparisons over CONUS

## RUC Cloud Assimilation

**Use multiple data types to modify cloud,**
**hydrometeor, and moisture fields:**
- -- NESDIS GOES cloud-top pressure/temp
- 		(implemented in 2002 w/ RUC20)
- -- Surface METAR (clouds, weather, visibility)
- 		(2005 w/ RUC13)
-  Construct 3-d logical arrays (YES/NO/UNKNOWN)
- 	for clouds and precipitation from all info
-  Clear/build moisture, cloud, precipitation fields
-  Safeguards for known problems (marine stratus,
- 	convective clouds, snow, nocturnal inversion)

## Satellite Validation

## LaRC and NESDIS Cloud  Top Height Comparisons with ARM ARSCL data

*Smith et al. 2008 (GRL)*

*5-yr dataset*
*Single-layer clouds*

- Satellite-derived Cloud Top Height
- Bias Errors (km)

## Satellite Liquid Water Path Validation

**Dong et al., JGR, 2007**

-  Unbiased over wide range of LWP (up to 500 g/m2)
-  Excellent correlation
-  Instantaneous Uncertainty ~30%
-  Note mean value ~150 g/m2

## Cloud Ice Water Path (From Waliser et al. 2008)

**LaRC CERES (analogous to LaRC GOES) compares well with CloudSat IWP**

## Instantaneous matched GOES-CloudSat Water Path1930 UTC, 1 March 2007

**Instantaneous matched GOES-CloudSat Water Path****1930 UTC, 1 March 2007**

- CloudSat Reflectivity

## GOES Cloud Water Path Comparisons with Cloudsat

**GOES Cloud Water Path Comparisons with Cloudsat**
**Dec 2006 – May 2007**

**• ****Excellent agreement between GOES and Cloudsat monthly mean total water path for high thick clouds.**
**• ****Thin ice cloud IWP also in good agreement**
**• ****LWP from Cloudsat is unreliable**

- Statistical Summary for All Months

## GOES/RUC Cloud Parameter Comparisons

## Matching Procedures

- Spatial Matching:  GOES 8-km pixel products averaged to RUC 20 km grid.
- Temporal Matching:  1745 UTC GOES within 15 minutes of RUC analyses and forecasts with valid times at 18 UTC.
- RUC grid box either OVC or CLR.  GOES is OVC, CLR or PC
- RUC Total Water Path:  Computed from 5 species level mixing ratios (cloud water, cloud ice, rain water, snow, graupel).
- RUC Cloud Phase:  Only analyzed in the top layer.
- Comparisons shown here are stratified by cloud phase (I.e. clouds with either liquid or ice water tops

## Ice

- GOES INFRARED

- GOES VISIBLE

- GOES CLOUD TOP PHASE

- RUC CLOUD TOP PHASE (0-hr fcst)

- Example Cloud Top Phase Comparison - May 8, 2008 (1800 UTC)

- Liquid
- Mixed
- SLW
- Clear

**Notes:**
More red (ice cloud) in ruc,  more warm water clouds in GOES

## 2007 Cloud/Clear Frequency Comparison (%) 

- 2007 Cloud/Clear Frequency Comparison (%)

|  | GOES | RUC 0-hr | RUC 1-hr | RUC 3-hr | RUC 6-hr |
| --- | --- | --- | --- | --- | --- |
| CLEAR | 33 | 43  | 45 | 47 | 47 |
| PC | 19 | NA | NA | NA | NA |
| OVC | 48 | 57 | 56 | 53 | 53 |
| ICE | 18 | 40 | 43 | 37 | 25 |
| LIQUID | 21 | 12 | 12 | 14 | 16 |

## 2007 Cloud/Clear Frequency Comparison (%) 

- 2007 Cloud/Clear Frequency Comparison (%)

|  | GOES | RUC 0-hr | RUC 1-hr | RUC 3-hr | RUC 6-hr |
| --- | --- | --- | --- | --- | --- |
| CLEAR | 33 | 43  | 45 | 47 | 47 |
| PC | 19 | NA | NA | NA | NA |
| OVC | 48 | 57 | 56 | 53 | 53 |
| ICE | 18 | 40 | 43 | 37 | 25 |
| LIQUID | 21 | 12 | 12 | 14 | 16 |

## RUC/GOES CLOUD FREQUENCY DIFFERENCES (%)FOR LAND and OCEAN

- RUC/GOES CLOUD FREQUENCY DIFFERENCES (%)FOR LAND and OCEAN

- RUC ANALYSIS minus GOES

- RUC ANALYSIS minus GOES

- Land

- Ocean

- All clouds
- Ice
- Liquid

- 3
- 22
- -10

- 10
- 19
- -4

- Land

- Ocean

- All clouds
- Ice
- Liquid

- 3
- 23
- -10

- 10
- 15
- 0

- 2007 dataset

- 2008 dataset

*RUC has too much high-level ice cloud (land & ocean) and too little low-level liquid cloud (over land) relative to GOES.*

## RUC Cloud Frequencies with and without NESDIS Satellite Data Compared to LaRC GOES

- RUC Cloud Frequencies with and without NESDIS Satellite Data Compared to LaRC GOES

- RUC

- GOES

- All clouds
- Ice
- Liquid

- 79
- 68
- 5

- 77
- 33
- 29

- RUC

- GOES

- All clouds
- Ice
- Liquid

- 54
- 38
- 10

- 44
- 16
- 17

- (Lat > 50 ̊ N)

- (Lat ≤ 50 ̊ N)

*Low-level liquid cloud frequency difference largest over Canada where no satellite data are used.  Large ice cloud frequency differences in both regions.*

- No NESDIS Data

- With NESDIS Data

## Distribution of Ice Cloud Frequency for GOES and RUC (2008)

- Distribution of Ice Cloud Frequency for GOES and RUC (2008)

- Relative Frequency (%) of
- Total Water Path for
- Clouds with Ice Phase Tops

*2008 Test Dataset*

*35% of the ice cloud difference is found in the lowest bin*

- Other possible reasons for discrepancy:
-  Cloud phase differences (mixed phase regime)
-  Poor GOES phase ID (multilayer systems)

## RUC CLEAR/CLOUD FREQUENCIES FOR 

- RUC CLEAR/CLOUD FREQUENCIES FOR
- GOES 100% OVERCAST REGIONS

- 2008

- 2007

## RUC CLEAR/CLOUD FREQUENCIES FOR 

- RUC CLEAR/CLOUD FREQUENCIES FOR
- GOES 100% CLEAR REGIONS

- 2008

- 2007

## RUC CLOUD FREQUENCIES FOR 

- RUC CLOUD FREQUENCIES FOR
- GOES OVERCAST ICE CLOUD REGIONS

- 2008

- 2007

## RUC CLOUD FREQUENCIES FOR 

- RUC CLOUD FREQUENCIES FOR
- GOES OVERCAST LIQUID CLOUD REGIONS

- 2008

- 2007

## Water Path Comparison Nov 8, 2008 (1800 UTC)

- GOES WP

- GOES minus RUC WP

- RUC WP

- GOES Cloud Phase

## Liquid Water Cloud Parameter Comparison

- Ocean

- Land

-  GOES LWP >> RUC LWP,  2008 RUC compares better
-  LaRC GOES cloud top heights and thicknesses exceed RUC values
-  Accounting for cloud thickness differences would yield better LWP       agreement over Ocean but not Land.

## Ice Cloud Parameter Comparison

- Ocean

- Land

-  GOES IWP >> RUC IWP
-  LaRC GOES and RUC cloud top heights agree for Analyses
-  RUC forecasted cloud top height exceeds GOES by over 0.5 km
-  GOES cloud thickness likely underestimated (poor Deep Convective estimates)
-  Land/Ocean differences generally consistent

## Summary

- The RUC is one of the more advanced NWP models worldwide that assimilates cloud observations.
- Comparison of RUC cloud parameters with similar parameters derived from GOES indicate the RUC assimilation works reasonably well.
- However, significant differences have been identified that exceed the satellite-derived uncertainties which implies that assimilation of  LaRC GOES-derived cloud products could lead to improved cloud analyses and forecasts in the model.
- Results from this study are being used to guide the assimilation of satellite-derived cloud parameters and also provide a baseline for future model evaluations.

## Extra slides

## Regional Liquid Water Path Comparison (g/m2)

- Regional Liquid Water Path Comparison (g/m2)

- 2008

- Poor agreement over the Atlantic but good
- over Pacific and Gulf of Mexico

## Regional Ice Water Path Comparison (g/m2)

- Regional Ice Water Path Comparison (g/m2)

- 2008

- RUC does track GOES regional differences.

## Cloud Ice Water Path (From Waliser et al. 2008)

**CERES-MODIS most similar to CloudSat values**

**CloudSat**

**CERES-MODIS**

**ISCCP**

**MODIS MYD06**