# Presentation: 687634

## Stan Benjamin, Bill Moninger, Tracy Lorraine Smith, Brian Jamison, Ed Szoke, Tom SchlatterNOAA Earth System Research Laboratory (ESRL), Global Systems Division (GSD)Boulder, CO

**Stan Benjamin, Bill Moninger, ****Tracy Lorraine Smith, Brian Jamison, Ed Szoke, Tom Schlatter**NOAA Earth System Research Laboratory (ESRL), Global Systems Division (GSD)Boulder, CO

## Purpose for Rapid Update Cycle (RUC) model run operationally at NCEP

**Provide high-frequency (hourly) mesoscale analyses, short-range model forecasts**
**Assimilate all available observations**
**Users:**
** ****aviation/transportation**
** ****severe weather forecasting**
** ****general public forecasting**
**Focus on 1-12 hour forecast range**
***KEY QUESTION:  Can TAMDAR add to RH/T/V forecast skill in RUC model****** ******competing with other obs******?***

**Purpose for Rapid Update Cycle (RUC) model run operationally ****at NCEP**

## Observation needs for aviation NWP addressed by deployment of automated weather data from regional carriers

- _Goal:  Improved forecasts for aviation hazards_ –
-  Icing, low ceiling conditions, precipitation forecasts
-  Convective environment, especially for convective initiation (T, RH, V - all important)
-  Lower tropospheric wind profiles (e.g.,CTAS)
- 			via
- High density (regional airports) high-frequency (>6-8 soundings/day)
-  temperature and moisture profiles
-  winds from ascent/descent, enroute
***=> Examine tropospheric profile of T/RH/V forecast skill***

##  Dev cycle – all obs data but no TAMDAR

** ****Parallel 20km RUC 1-h cycles**
**  ****Uses latest code in RUC13 (but at 20km)**
** ****Dev ****cycle – all obs data but ****no TAMDAR**
** ****Dev2**** cycle – dev ****+ TAMDAR**** data**
** ****Lateral boundary conditions – same for Dev and Dev2**
** ****Control design**
** ****Initialize Dev and Dev2 runs at exact same time – same observations used (except TAMDAR)**
** ****Reset dev and dev-2 background field at 1000z every **
**48 h **
** ****Ensure against any computer processing differences between dev and dev2 cycles**

## 1000-1800z

**1000-1800z**

**Dev-Dev2 difference – 0h analysis**
**Init 1800z 24 Aug 2005 – 500 mb**

## Verification regions for GSD-RUC TAMDAR impact 

_**Verification regions for GSD-RUC TAMDAR impact**_** **
**Large region (eastern half of US) --  38 RAOB sites**
***Small region (Great Lakes) includes 14 RAOBs***

## Key dates for RUC analysis/QC changes

_**Key dates for RUC analysis/QC changes**_
** ****8 June 2005  - Introduction of improved aircraft reject list**
** ****1 Sept 2005 – Updated reject list**
** ****15 Sept 2005 – Incorporate RUC13 moisture analysis**
** ****15 Nov 2005 – Add new QC step in RUC analysis using ob-background (O-B) difference – (important for isolated observations)**
**  ****1 Dec 2005 – Revised aircraft RH observation error to higher value (4% to 12%, now same as raob, was previously “overfitting” TAMDAR RH data)**
** ****15 Dec 2005 – Flag TAMDAR winds on descent**
** ****15-30 March 2006 – Incorrect use of TAMDAR-RH in dev2.  Corrected on 31 March**
** ****June 2006 – Further improvement in O-B QC**

## New verification software – Bill Moninger

-  - verify every 10mb, not just at mandatory levels
-  - use all raob data, no QC screening
- Example - More improvement in 500mb RH forecasts
- from TAMDAR from including all obs.

## Temp errors vs. raobs

**Temp errors vs. raobs**
**– ****850 mb  **

-  3h fcsts
-  Valid 00z
-  Gt.Lakes region
-  Running 30-day avg

- Dev –no TAMDAR
- Dev2- w/TAMDAR

-  *Strongest effect at this level – 0.25 C improvement*
* **Slightly improved in 2006*

## Temp errors vs. raobs

**Temp errors vs. raobs**
**– ****1000-800 mb avg  **

-  3h fcsts
-  Valid 00z
-  Gt.Lakes region
-  Running 7-day avg

-  *Most accurate results in 2006 since mid-Nov*

- Dev –no TAMDAR
- Dev2- w/TAMDAR
- Diff – dev-dev2

## Wind errors vs. raobs

**Wind errors vs. raobs**
**– ****850-700-500 mb avg  **

-  3h fcsts
-  Valid 00z
-  Gt.Lakes region
-  Running 30-day avg

-  *Consistent improvement from TAMDAR*

- Dev –no TAMDAR
- Dev2- w/TAMDAR
- 3h persistence –dev2

## RH errors vs. raobs

**RH errors vs. raobs**
**– ****850-700-500 mb avg  **

* **Consistently positive since Jan 2006*

-  3h fcsts
-  Valid 00z
-  Gt.Lakes region
-  Running 30-day avg

- Dev –no TAMDAR
- Dev2- w/TAMDAR
- 3h persistence –dev2

## RH errors vs. raobs

**RH errors vs. raobs**
**– ****850 mb  **

-  3h fcsts
-  Valid 00z
-  Gt.Lakes region
-  Running 30-day avg

-  *Consistent positive impact from TAMDAR in 2006, unlike in 2005*

- Dev –no TAMDAR
- Dev2- w/TAMDAR

## RH errors vs. raobs

**RH errors vs. raobs**
**– ****sfc-800 mb avg  **

-  *Positive impact throughout 2006*
* **Average 1% in 1000-800mb layer*

-  3h fcsts
-  Valid 00z
-  Gt.Lakes region
-  Running 7-day avg

- Dev –no TAMDAR
- Dev2- w/TAMDAR
- 3h persistence –dev2

## RH errors vs. raobs

**RH errors vs. raobs**
**– ****900-500 mb avg  **

-  *Increased impact in last 3 months*

-  3h fcsts
-  Valid 00z
-  Gt.Lakes region
-  Running 7-day avg

- Dev –no TAMDAR
- Dev2- w/TAMDAR
- 3h persistence –dev2

## April-October 2006

*Temperature *

- wTAM

- noTAM

- Warm season + transition

- Dec06-Jan07
- Cold season

- wTAM

- noTAM

## April-October 2006

*Relative humidity*

- wTAM

- noTAM

- Warm season + transition

- Dec06-Jan07
- Cold season

- wTAM

- noTAM

## April-October 2006

*Wind*

- wTAM

- noTAM

- Warm season + transition

- wTAM

- noTAM

- Dec06-Jan07
- Cold season

## TAMDAR impact study with RUC parallel cycles

- _TAMDAR impact study with RUC parallel cycles_
-  2005-2007 (ongoing)
- Further improvement in
- RH, temperature, wind

- Forecast errors – RUCdev (no TAMDAR), RUCdev2 (w/ TAMDAR)

- noTAM

- wTAM

*Temp*

*RH*

*Wind*

- wTAM

- wTAM

- noTAM

- noTAM

## GSD-RUC TAMDAR impact experiment results – updated 17Jan 2007

**GSD-RUC TAMDAR impact experiment results ****– updated 17Jan 2007**
-  Recent results – *2006*
-   RH impact improved in 2006 – Consistent 1-2%RH reduction of RMS error   (20-30% reduction – peaks at 900-800mb, 600-400mb
-  Temperature impact
-  strongest from 950-800mb layer – inversion top!
-  25% reduction of 3h forecast error (0.25K)
-  Better temp impact apparent w/ higher vert resolution (Nov06-current)
-  Wind impact – ~10% reduction of 3h fcst errors in 850-700-500mb layer.  About same as in 2005.
-  Heading accuracy w/ Saab/Mesaba winds
-  Increase turboprop wind obs errors?
- (now used in devRUC13).
-   Results (TAMDAR impact) have improved during continued TAMDAR evaluation