# Presentation: 096577

## Stan Benjamin, Bill Moninger, Tracy Lorraine Smith, Brian Jamison, and Barry SchwartzNOAA Earth System Research Laboratory (ESRL), Global Systems Division (GSD)Boulder, CO

***-- update - 13 April 2006***

**Stan Benjamin, Bill Moninger, ****Tracy Lorraine Smith, Brian Jamison, and Barry Schwartz**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 forecast skill for 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

- _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 850-500mb 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 logistics differences**

## 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***

## TAMDAR evaluation phases

**9 Feb – 21 April 2005**
** ****Winter/early spring – lower vertical resolution**
**22 April – 1 June**
** ****Spring – **_**higher vertical resolution**_
**2 June – 22 July**
** ****Summer – **_**higher vertical resolution**_
**23 July – 24 August**
** ****Summer – lower vertical resolution**
**25 August – Jan 2006 – lower vert res**
**31 March 2006 – onward  – back to **_**higher vertical resolution**_

## 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 difference – (important for isolated observations)**
**  ****1 Dec 2005 – Revised aircraft RH observation error to higher value (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.**

## Temp errors vs. raobs

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

- Dev –no TAMDAR
- Dev2- w/TAMDAR

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

-  *Consistent improvement from TAMDAR*
* **Increasing in winter 05-06*

## Temp errors vs. raobs

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

- Dev –no TAMDAR
- Dev2- w/TAMDAR

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

-  *Strongest effect at this level – 0.25 C improvement*
* **inversions, cloud/thunderstorms/CAPE/CIN, etc.*

## Temp errors vs. raobs

**Temp errors vs. raobs**
**– ****850 mb only – **_***eastern US***_** **

- Dev –no TAMDAR
- Dev2- w/TAMDAR

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

-  *About 0.15 C improvement overall over eastern US*

-  3h fcsts
-  Valid 00z
-  **Eastern US domain – 38 raobs**
-  Running 30-day avg

## Temp errors vs. raobs

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

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

-  *Consistent improvement from TAMDAR*
* **Increasing in winter 05-06*

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

## Wind errors vs. raobs

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

- Dev –no TAMDAR
- Dev2- w/TAMDAR

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

-  *Consistent improvement from TAMDAR*

## 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

- Dev2 improvement

- Dev –no TAMDAR
- Dev2- w/TAMDAR

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

-  *Positive impact from TAMDAR in last 2 months*
* **Irregular in 2005*

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

## RH errors vs. raobs

- Dev2 improvement

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

-  *Positive impact from TAMDAR in last 4 months*
* **Irregular in 2005*

-  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**
**– ****850-700-500 mb avg  **

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

- Dev –no TAMDAR
- Dev2- w/TAMDAR

## RH errors vs. raobs

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

-  3h fcsts
-  Valid 00z
-  Gt.Lakes region
-  No avg

- Dev –no TAMDAR
- Dev2- w/TAMDAR

- - ~1% RH reduced error w/ TAMDAR in April

## Overall GSD-RUC TAMDAR impact experiment results – updated 13 April 2006

**Overall GSD-RUC TAMDAR impact experiment results ****– updated 13 April 2006**
-  Results (TAMDAR impact) have improved during continued TAMDAR shakedown phase
* **Impact in cases often much larger than overall statistics*
-  Recent results – *Jan-April 2006*
-  Temperature impact
-  strongest (best) at 850 mb
-  25% reduction of 3h forecast error (0.25K)
-  20% on average – 850-700-500 mb
-  RH impact – 10% reduction RMS error (last 4 months – Dec05-Apr06)   (15-20% reduction – 850mb, April06)
-  Better Temp/RH impact w/ higher vert resolution
-  Wind impact – ~10% reduction of 3h fcst errors in 850-700-500mb layer
-  Heading accuracy w/ Saab/Mesaba winds
-  Use along-track winds only? Maybe.
-  Increase turboprop wind obs errors? Definitely.