# Presentation: 200384

## Verification Statistics for the NCEP WRF Pre-Implementation Test. Part 1: Deterministic Verification of Ensemble Members

- Ligia Bernardet NOAA FSL
- Louisa Nance NCAR DTC
- Hui-ya Chuang NCEP
- Andrew Loughe NOAA FSL
- Steven Koch NOAA FSL
- May 27, 2004

## Topics	

- Initial Conditions
- Forecast
- Vertical Profiles
- Temperature
- Wind
- Relative Humidity
- Surface
- Temperature
- Sea Level Pressure
- Relative Humidity
- Focus: main features and grouping

## Initial Conditions: Temperature                      May - Central

- EM initializations do not vary with physics swap
- Same for NMM
- At t=0, breeding pair has bias encompassing baseline (?250)
- Breeding of EM, NMM IC causes diversity

- EM has smaller Temperature bias and RMSE than NMM
- This is true for winds too, but not for relative humidity

## Initial Conditions: Relative Humidity              August - Central

- EM, NMM dry at midlevels
- NMM has better fit to obs then EM

## Forecast: Temperature                                    October - East

- EM bias to the left
- Primary grouping by dynamical  core
- Physics important at low levels

- Most seasons/domains have a cold bias at low level and a warm bias aloft
- In winter, NMM has a warm bias at 850 hPa.

## Forecast: Vector Wind                                       May - Central 

- Bias is mostly negative
- Large errors at jet level
- No obvious grouping in all seasons but winter

- Forecast: Vector Wind                                       May - Central

## Forecast: Vector Wind                                 February - East

- Winter: grouping by dynamical core
- Large errors at jet level

## Forecast: Relative Humidity                       August - West 

- Bias850= all close
- Bias700= dyn core
- Bias500= dyn core
- Bias400= phys
- Bias300= phys
- ... but varies with season/domain
- RH: only field for which physics leads to obvious grouping at upper levels (cumulus transport?)
- RMSE smallest at 850, max at midlevels and reduce upwards (exception Winter E, errors large at 850 hPa)

- RH is the variable with largest variability
- among seasons and domains

- Forecast: Relative Humidity                       August - West

## Forecast: 2m Temperature                       February - West

- day

- night

- day

- Bias:
- Grouping by dynamic core - especially daytime.
- Physics swaps causes member to differentiate from group - esp. night.
- Diurnal cycle: at TMAX, EM cold, NMM warm.

- Swapped physics is not between parent models
- Physics causes large differentiation
- No obvious grouping in RMSE

## Forecast: 2m Temperature                          February - East 

- day

- night

- night

- Bias:
- Diurnal oscillation is less evident for **all variables** in E domain
- Obvious grouping by dynamic core
- All forecast times, EM cold,
- NMM warm.

- Swapped physics is not between parent models
- Physics causes smaller differentiation

- Forecast: 2m Temperature                          February - East

## Forecast: Sea Level Pressure                               May - Central 

- Bias:
- Most models underpredicted SLP.
- All domains but E: diurnal cycle with SLP low at Tmax at SLP high at Tmin
- Grouping by dynamic core

- ETA overall lowest RMSE

- Forecast: Sea Level Pressure                               May - Central

- day

- night

- night

## Forecast: Sea Level Pressure                      October - East 

- Bias:
- E domain: no diurnal cycle
- Most models underpredicted SLP, but NMM closer to zero bias
- Strong grouping by dynamic core
- Error grows with time

- Forecast: Sea Level Pressure                      October - East

- day

- night

- night

## Forecast: Surface Relative Humidity          August - Central

- Strong diurnal cycle in most seasons/domains
- Underprediction by all models, especially at night
- Not obvious grouping

- night

- day

- night

## Forecast: 24 hr acc Precipitation                  October - East 

- Bias:
- Grouping by physics
- NCAR physics (K-F convection) overpredicts at high thresholds (or is it lack of mesoscale obs?)
- ETS similar for all models, except on W domain, where ETA is best

- Forecast: 24 hr acc Precipitation                  October - East

## Summary

- Initial Conditions
- Bias/RMSE near zero in low-mid trop, positive bias at 200 hPa
- EM has better fit to observations in all variables, except RH
- Remarkable result, since ETA uses its own assimilation system
- Shows that RUC analysis has strong fit to RAOBS

## Upper Air
Results group mostly by dynamical core/IC.
Temperature
Cold bias at low levels, warm above.
Physics grouping in lower troposphere (PBL scheme?) 
Wind
Mostly underprediction.
Largest errors at jet level.
In winter, grouping by dynamical core.
Other seasons, no grouping.
RH
Smaller errors at low and upper levels; largest errors at 500 hPa.
Physics grouping in upper troposphere (cumulus transport?)

- Results group mostly by dynamical core/IC.
- Temperature
- Cold bias at low levels, warm above.
- Physics grouping in lower troposphere (PBL scheme?)
- Wind
- Mostly underprediction.
- Largest errors at jet level.
- In winter, grouping by dynamical core.
- Other seasons, no grouping.
- RH
- Smaller errors at low and upper levels; largest errors at 500 hPa.
- Physics grouping in upper troposphere (cumulus transport?)

## Surface
Temperature
Diurnal cycle, except E.
At Tmax, EM too cold, NMM too warm - group by dynamical core.
At night, physics plays a role.
Physics swap does not follow parent models.

Sea Level Pressure
Diurnal cycle, except E.
Grouping by dynamical core
RH
Strong diurnal cycle in most seasons/domains
Underprediction, especially at night
Not obvious grouping

- Temperature
- Diurnal cycle, except E.
- At Tmax, EM too cold, NMM too warm - group by dynamical core.
- At night, physics plays a role.
- Physics swap does not follow parent models.
- Sea Level Pressure
- Diurnal cycle, except E.
- Grouping by dynamical core
- RH
- Strong diurnal cycle in most seasons/domains
- Underprediction, especially at night
- Not obvious grouping

## Other material

## Physics Options