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Impact of the NAME04 Soundings on the NCEP data

assimilation systems

Kingtse Mo, Eric Rogers, Wesley Wesley EbisuzakiEbisuzaki, R. Wayne Higgins, Jack

Wollen and Marco Carrera

Climate Prediction Center NOAA/NWS/NCEP

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NAME04 Special Upper Air Soundings

During the EOP

Altair, Yuma did not get onto the GTS;

25% Loreto data did not get in.

All other stations had less than 10 reports missing.

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Data Impact Experiments

NAME04 EOP (1 July – 15 August,2004)

Experiments accomplished:• CDASw, CDASwt, CDASwtmex• GDASw;• RCDASw, RCDASwt, RCDASwtmex• EDASw, EDASwt. EDASwtmex

DASw is the operational product

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Global and regional data assimilation systems

GLOBAL:CDAS2 (Climate Data Assimilation System): T62L28 The CMAP precipitation is used to adjust soil moisture, but no direct assimilation of P

GDAS (Global Data Assimilation System) :T254T64 model. No P assimilation

Regional : EDAS: ( Eta model 3D-Var Data Assimilation system) 12KM 60 layers. It assimilates radar precipitation data over the continental US.

RCDAS ( Regional Climate Data Assimilation System) 32Km, 45 layers, It assimilates P .

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INPUT data

Input data In all assimilation systems• All systems use rawinsondes, dropsondes, cloud drift

winds from Geostationary satellite and aircraft data getting into the buffer.

• They all use the TOVS-1B radiance data

Major differences• Both the GDAS and EDAS use more satellite

observations than the CDAS2 and RCDAS: SSM/I wind speeds, TRMM TMI precipitation estimates, NOAA-15, NOAA-16 AMSU-A 1b radiances and NOAA-15 –16 and –17 AMSU-B 1b radiances

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Ratio= diff**2/varZ500 V850CDASw-CDASwt

CDASw-CDASwtmex

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P over the EOPobs

CDASw

CDAS wt

CDAS wtmex

Improvement over the SMO, but not over the AZNM area

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Vertically integrated moisture flux (vector) (qv,contoured)

GDAS

CDAS w

CDAS wt

Diff

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Puerto Penasco

31.18N, 113-33W

The CDASw really tries,But the coarse resolution Model is not able to take advantage of the soundings

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Conclusions

1. The impact of the NAME 04 soundings is largely local and is concentrated over the NAME core region;

2. Over the monsoon region, rainfall improves with soundings, but the coarse resolution model Is not able to take advantage of the soundings to improve the moisture fluxes

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• 2.

1. Differences of the NAME Soundings are local and concentrated over the Tier I area for both RCDAS and EDAS.

2. At upper level, the impact on winds and

Circulations are similar for the RCDAS and the EDAS

RCDAS EDAS

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[qv] (contoured) and [qu,qv] flux(vector) with soundings

1. GPLLJ:

The GPLLJ from RCDASw

and RCDASwt, GDAS are

similar,while the EDASDwt

shows a stronger jet.

2. The GCLLJ from the GDAS,

and EDASw and EDASwt

are similar, while the RCDAS

depicts a very strong jet with

a center over the Gulf

of California

Units:kg m-1s-1

EDASw

EDASwt

RCDASw

RCDASwt

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a) Obs soundings[qv] at Puerto Penasco

(31.3N, 113.5W) at northern Gulf of California.

unit is (g/kg)(m/s)

When the soundings are assimilated, the differences between the observations , EDAS and RCDAS are close. When the soundings are taken out, the differences are greater than 60 (k/kg)(m/s)

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[qu,qv] anomalies for 3 surge events

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Impact of soundings on the EDAS fcstsCMORPH

EDAS day 2-3

EDASw-EDASwt day 2-3 fcsts

EDASw-EDASwt 3hr fcsts

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Conclusions

• The impact of the NAME04 special soundings on global and regional analyses and short range forecasts is largely local and is concentrated over the Tier 1 area.

• The impact on analyses differs from system to system. Overall, the soundings will correct some uncertainties in the assimilation system and improve the analyses

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Conclusions

• EDAS:The NAME soundings improve the magnitude and location of the GPLLJ and improve rainfall over northeastern Mexico.

• RCDAS: Soundings improve the GCLLJ

• Soundings will improve analyses somewhat, but they will not correct all errors in the system.

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Qfluxes

IMPACT on qfluxes for EDAS

IMPACT for RCDAS

Differences between

EDASw and RCDAS w

qv qu

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Experiments w/wt P assimilation

• Four experiments:• RCDASw(P): with P assimilation, with

soundings;• RCDASwt(P): with P assimilation, without

soundings;• RCDASw(no P): without P assimilation,

with soundings;• RCDASwt(no P): without P assimilation

and without soundings

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Precip from RCDAS EOP meanobs

RCDASw(P)

RCDASw(no P)

RCDASwt(no P)

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Vertical cross section of qv at 30NImpact of sndings w P Impact of sndings wt P

Impact of P w sndings Impact of P wt sndings

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T2m diff

RCDASw(P)-RCDASw (no P)

Impact due to P assimilation with soundings

RCDASwt(P)- RCDASwt(no P)

Impact due to P assimilation

Without soundings

RCDASw(P)-RCDASwt(P);

Impact due to soundings

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Temperature profile between soundings and molts

Black (with P with sndings);

Green (with P wt sndings)

blue (no P w sndings)

Red (no P wt sndings)

Over N Mexico,

The impact of P assimilation

Is larger than the NAME04 soundings

No P With P

Torreon

Chihuahua

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Conclusions

• The differences between analyses with and without soundings are smaller than the differences between two regional systems.

• The P assimilation has large impact on analyses, but the impact differs from the soundings

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Goal:Prediction of summer precipitation over

the United States and Mexico

Challenges:

1. Truth: Analyses depend on the model, assimilation system and data inputs. The differences can be very large.

We have more than one version of the “Truth”, what are we going to do

about?

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Analyses

• Analyses can only be as good as the model, assimilation system and the input data including precipitation;

• Impact of soundings on short range forecasts is small. Why?

• 1. No changes on long waves;

• 2. Model’s convection has problems;

• 3. Targeting?

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P assimilation (Lin et al. 2004)

• Compare the model P and observed P;

• Change the latent heating profile , water vapor mixing ratio and cloud water fields

P (assimilation) is close to P obs;Changes in E and soil moisture

and changes in temperature profile.

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Difference in moisture transportImpact of Soundings w P Impact of Sndings no P

P impact w sndings P impact wt sndings

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Input data differences among the NCEP data assimilation systems

Not usedUsedUsedNOAA-15 –16 and –17 AMSU-B 1b radiance s

Not usedUsedUsedNOAA-15, NOAA-16 AMSU-A 1b radiances

Not usedNot usedUsed over land

GOES precipitable water

Precipitation included through variational scheme and model physics

Not usedUsedNot usedTRMM TMI precipitation estimates

Precipitation included through variational scheme and model physics

Not usedUsedNot usedSSM/I precipitation estimates

Not usedNot usedUsed SSM/I precipitable water

Not usedUsedNot usedQuickscat wind speed and direction

Not usedAssigns direction from guess

Used directly

SSM/I wind speeds

u,v T, s and qFrom the COADS

u, v, T, Ps, qu, v, T, Ps, qSurface ship and buoy observations

Ps 10m winds,2m q

Psu, v, T, Ps, qSurface land observations

not usedu, vu, vGOES water vapor cloud top winds

u, vu, v, Tu, vGMS, METEOSAT,GOES cloud drift IR and visible winds

CommentsRegional CDAS

Eta operational GFSInput Data

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Vertically Integrated Meridional Moisture Flux (kg/ms) (1995-2000)

GCLLJ

RR Operational EDAS

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RR Operational EDAS

Vertical cross section of qv at 30N

1998-2000

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For the EOP period, 96-hr fcst was performed each day at 0Z,

The RSM errors for Z500 AND v850 over the PNA region (150W-60W,20-50N) is very small, but at 96 hr, the regional differences over the Gulf and the SMO regions are visible

RMS errorsICs CDAS w ICs CDAS wt

12h

24h

96 h