Introducing the Advanced Baseline Sounder (ABS)

NOAA/NESDIS/ORA in collaboration with

Cooperative Institute for Meteorological Satellite Studies Madison, Wisconsin

presented by Paul Menzel

UW-Madison

Using the Current GOES SounderImprovements Required

ABS SimulationsResults with Airborne Interferometers

Anticipated Capabilities

GOES Sounder Spectral Bands: 14.7 to 3.7 um & Vis

GOES Sounder Spectral Coverage Current instrument has 18 infrared bands.

Moisture Weighting Functions

Pre

ssur

e (h

Pa)

GOES (18)

1000

100

UW/CIMSS

GOES retrievals have limited vertical resolution.

Java animation: anigli3m.html

Evolution of stability seen in GOES LI DPI

(12 to 18 UT)

12

14

16

18

Java animation: anisks3m.html

Evolution of profiles retrieved from the GOES Sounder

(12 to 18 UT)

View from ground

View from spaceOK tornado 3 May 99

530 CDT (2330 UTC)

1800 UTC

2300 UTC

Record Earliest Tornado at Milwaukee, WI on 8 Mar 2000

• The GOES-8 Sounder monitors important precursors to the event.

• More information on the web: http://cimss.ssec.wisc.edu/goes/misc

moist axis

dry slot(dark areas)

Retrieval correctly subtracting moisture aloft (within the mid-level dry intrusion)

Retrieval correctly adding moisture in the lower

levels (within the moist axis)

GOES Retrieval

First Guess

(S.E. WI)

GOES axis of high LI indicates subsequent storm track 24 Jul 2000

NWS Forecast Office Assessment of GOES Sounder Total Precipitable Water

Summer 99 Forecaster assessment of usefulness of changes in hourly TPW product for precipitation forecast

Out of 207 weather cases.- Significant Positive Impact (21.3%)- Slight Positive Impact (50.2%)- No Discernible Impact (27%)- Slight Negative Impact (1%)- Significant Negative Impact (<1%)

Figure from the National Weather Service, Office of Services

NWS Forecast Office Assessment of GOES Sounder Atmospheric Instability

Summer 99 Forecaster assessment of usefulness of changes in hourly LI, CAPE, & CINH product for predicting location/timing of thunderstorms

There were 248 valid weather cases.- Significant Positive Impact (30%)- Slight Positive Impact (49%)- No Discernible Impact (19%)- Slight Negative Impact (2%)- Significant Negative Impact (0)

Figure from the National Weather Service, Office of Services

Eta Data Assimilation System Satellite Data Impact Study for 3 Seasons

24-hr forecast for Temperature

24-hr forecast for Relative Humidity

Positive Impact due to GOES sounder PW (marine)Positive Impact due to Radiosonde (T and moisture)Ratio =

A Ratio greater than 1 means the satellite improved the forecast more than the radiosondesover the entire domain (land and marine)

GOES Sounder Moisture Impact on Eta (Zapotocny et al., 2001)NoGOES / NoRAOB for 10 days in 3 seasons

* Current GOES sounder resolves three tropospheric layers of temperature and moisture every 50 km in clear skies over CONUS plus; in cloudy skies it determines cloud top properties. It is filling gaps in conventional and polar orbiting observing systems.

* GOES sounder depiction of changes in time and space are being embraced by the NWS forecast offices

* NWP impact from three layers of GOES moisture is positive in Eta model. But, full worth of geostationary data not yet realized; 4-DVAR strategies offer hope.

* Revisit of NWS user requirements suggested more coverage and better vertical resolution are the key improvements

* Beyond NWP, there are other areas where GOES data can be useful but metrics are elusive

ABS User Requirements (1999 NWS Thresholds)

Resolutions - Temporal: ‘sounding disk’ in 1 hour - Spectral: like LEOs from 3.7-15.4 µm with 0.6 to 2.5 cm-1 res - Spatial: 10 km horizontal res for independent obs - Spatial: 1 km vertical for temp, 2 km for moisture

•Accuracies 1 degree K temperature; 10% relative humidity

•Applications - Nowcasting - Short-range weather forecasting - Longer-range numerical weather prediction

Sounder Comparison (GOES-Current to ABS-Req)

Coverage Rate CONUS/hr Sounding Disk/hr

Horizontal Resolution

- Sampling Distance 10 km 10 km

- Individual Sounding 30-50 km 10 km

Vertical resolution ~3 km 1 km

Accuracy

Temperature 2 deg. K 1 deg. K

Relative Humidity 20% 10%

Current Requirement

Areas within 62 degrees local zenith angle from GOES-East and GOES-West sub-satellite points are indicated. Threshold coverage rate calls for the 62 arc region, excluding half of over-lap, to be scanned each hour. Current GOES -E and -W sounder hourly coverage is also shown.

SpatialCoverage

UW-Madison/CIMSS

GOES Sounder Spectral Coverage Current instrument has 18 infrared bands.

Future instrument will have more than 1400 infrared bands.

Higher spectral resolution leads to improved vertical resolving power.

Spectral coverage of the ABS, GIFTS, IASI and the current GOES

radiometer sounder

ABS:

Moisture Weighting Functions

Pre

ssur

e (h

Pa)

Pre

ssur

e (h

Pa)

Advanced Sounder (3074)

GOES (18)

1000 1000

100 100

UW/CIMSS

High spectral resolution advanced sounder will have more and sharper weighting functions compared to current GOES

sounder. Retrievals will have better vertical resolution.

The advanced sounder has more and sharper weighting functions

UW/CIMSS

These water vapor weighting functions reflect the radiance sensitivity of the specific channels to a water vapor % change at a specific level (equivalent to dR/dlnq scaled by dlnp).

Moisture Weighting Functions

Pre

ssur

e

Weighting Function AmplitudeWavenumber (cm-1)

Detection of Temperature Inversions Possible with Interferometer

Detection of inversions is critical for severe weather forecasting. Combined with improved low-level moisture depiction, essential

ingredients for night-time severe storm development over Plains can be monitored. Knowing if there is an inversion can also help

improve profile estimates.

Spikes down - Cooling with height

Spikes up -Heating with height

Texas

Ontario

Bri

ghtn

ess

Tem

pera

ture

(K

)

(low-level inversion)

(No inversion)

GOESGOES

Wavenumber (cm-1)

WV vertical structure revealed with Geo-Interferometer

Alt

itud

e, k

m

Two flight tracks from NAST-I

during CAMEX-3 September 14, 1998

--------------------------125 km-------------------------

RH %

The 19 channels from the current GOES sounder

Sounder spectral coverage over Oklahoma.UW-Madison/CIMSSNOAA/NESDIS/ORA

ABS TRD noise (upper) and CrIS brightness temperature spectra (lower) calculated for low level temperature inversion

ABS/CrIS vs GOES retrieval for low level temperature inversion

Current retrieval strategy:- use all channels in a regression for first guess

- then use a sub-set of channels for physical retrieval

Preliminary simulations of ABS/CrIS and GOES retrievals from 590 global radiosondes

Geo-I gets <1 K rms for 1 km T(p) and <10% rms for 2 km RH(p)

Simulated CrIS and GOES CTP rms for very high (about 200 hPa), high (about 300 hPa), medium (about 500 hPa), and low (about 850

hPa) clouds with ECA from 0.1 to 1.0 using 75 CONUS raobs.

Simulated Comparison of Current Sounder and ABS

Significant improvements in surface and total column parameters are made with interferometers

Analysis of NOAA global raob data (tropics and mid-lat summer)

VAS - pastGOES - currentG18 - 18 1/2cm-1 chsG50 - 50 1/2cm-1 chsABS - 2000+ 1/2cm-1 chs

RAOB - T to 150mb (Q to 300mb)

GOES Info Content for Moist Atmospheres

0

2

4

6

8

10

12

14

16

18

VAS GOES G-18 G-50 GAS RAOB

Instrument

Nu

mb

er o

f In

dep

end

ent

Pie

ces

of

Info

rmat

ion

Temperature

Water Vapor

Geo-Interferometer nears Raob-like depiction of atmosphere

25 cm Unapodized Aperture 13x13 FPA 10 Km FOV

0.001

0.01

0.1

1

500 1000 1500 2000 2500 3000

Wavenumber (cm-1)

NE

dN

(m

W/m

2 s

r cm

-1)

Total NEdN

Photon & Detector Noise

Amplifier Noise

Analog Filter Aliasing

Quantization

Mirror Velocity Error

Dynamic Mirror Alignment Error

25 cm Unapodized Aperture 12x12 FPA 8 Km FOV

0.001

0.01

0.1

1

500 1000 1500 2000 2500 3000

Wavenumber (cm-1)

NE

dN

(m

W/m

2 s

r cm

-1)

Total NEdN

Photon & Detector Noise

Amplifier Noise

Analog Filter Aliasing

Quantization

Mirror Velocity Error

Dynamic Mirror Alignment Error

Table 5. Maximum allowed NEdNT = 289 K

Wavenumber range(cm-1)

Max. NEdN[mW/(m2 sr cm-1)]

650 – 670 1.0670 – 685 0.7685 – 700 0.5700 – 1200 0.151210 – 1740 0.062150 – 2720 0.008

DMSP OLSnighttimecomposite

image

ABS Low-Light Visible Capability

4 km resolution

Due to the increased dwell times compared to an imager, the sounder visible data may be more sensitive in low-light regions.

Better depiction of near nighttime fog and thunderstorms. This may also improve knowledge of the location of the center of tropical disturbances.

Table 2. ABS Observational Requirements Summary (Partial List)

Requirement and Source ThresholdVisible 0.5 km FOV to enable

Accurate cloud-cover detectionSpatial resolution1,1

IR 10 km (280 rad) squareEnsquared energy2 At least 90% of energy incident on a detector

pixel must originate from a 10x10 km groundsample corresponding to this FOV

(see 3.B.2)The region within 62degrees local zenithangle (except onlyhalf of the over-lapregion between twosatellites)

Each hour,including any necessary allowance for IR

calibration and star sensing

Operational scenarios may deviate fromscanning the arc every hour, but this

coverage rate is needed to provide bothCONUS and a minimum adequate level of

ocean coverage

Spatial coveragerate

Regional andMesoscale

when required

Must be supported and selectable

Visible imaging star sensing 4 stars per half hourOperation during eclipse1 Yes

Radiance 3 minutesTimeliness of data1

Simultaneity1 Within 10 sec. for all bands at any FOV(Limits cloud encroachment in FOV to

< 10%)

1 Based on Phase A studies at MIT/LL2 P. Menzel, NESDIS

ABS User Requirements

After grd proc implied.Need far field spec: 99% of IRW energy within circle of 1 mr.

Table 5. Maximum allowed NEdNTest target

temperature (K)T = 289 K

Wavenumber range(cm-1)

Bin size (cm-1) Max. NEdN[mW/(m2 sr cm-1)]

650 – 670 0.625 1.0670 – 685 0.625 0.7685 – 700 0.625 0.5700 – 1200 0.625 0.151210 – 1740 1.25 0.062150 – 2720 2.50 0.008

ABS Signal-to-Noise

Navigation (Vis and IR)1 2.5 km ( 70 rad) at SSPRegistration within frame1 1.0 km ( 28 rad) at SSPIR band linearity See 3.B.2.jRegistration image to image Visible IR1

2.5 km ( 70 rad) in 30 min. 2.5 km ( 70 rad) in 30 min.

Visible-IR 1.0 km ( 28 rad)Band to band co-registration IR-IR1 1.0 km ( 28 rad)

(< 10% of FOV)

ABS Navigation and Registration

Want 10% FOV knowledge for band to band.

Want 10% within band registration for IRWs.

LWIR NEDNshould be 0.2 for most of LW band

Mass5 Should not exceed current N-Q sounderweight

Power5 Should not exceed current N-Q sounderpower

Volume5 Should not exceed current N-Q soundervolume

Data rate6 < 8 Megabits-per second (Mbps)Lifetime7 Ground storage 2 years

On-orbit storage 2-3 yearsMean Mission life 8.4 yearsDesign life 10 years

ABS Mass, Power, Volume, Data rate, Lifetime

Advanced Sounder: Improved Forecasts

• Advanced sounder provides data for...– Improved quantitative precipitation estimates and forecasts

– Reduced size of geographic area affected by Watches

– Improved early detection of severe weather & flash floods

– Improved forecasts of hail and hail size

– Improved detection of lake and sea ice through thin clouds

– Improved prediction of fog formation and dissipation

– Better microburst potential forecasts (aircraft wind shear; surface winds for transportation; visibility reduction reduction; fire control)

– Hurricane intensity and motion

– Nighttime major thunderstorm cluster development (formation of low-level inversion and moisture)

• Provides input data for mesoscale model initialization

Time series of low-level vertical temperature structure during9 hours prior to Oklahoma/Kansas tornadoes on 3 May 1999

Truth>

Geo-I>

Note Geo-I improves depiction

of boundary layer heating and

surface inversion

Current GOES>

Geo-I traces evolution of 800 hPa inversion with 60-80% error reduction

3 May 1999 – Oklahoma/Kansas tornado outbreak

Geo-I correctly captures the important vertical temperature variations

GIFTS/GOES Retrieved-Temperature Errors

Truth>

Geo-I Errors>Standard Deviation = 0. 6o

Note Geo-I reduces errors by

80% and captures 800mb inversion

GOES Errors>Standard Deviation = 3. 5o

Time series of low-level vertical moisture structure during9 hours prior to Oklahoma/Kansas tornadoes on 3 May 1999

Truth>

Geo-I>

Note Geo-I retains strong

vertical gradients for monitoring

convective instability

Current GOES>

Geo-I traces moisture peaks and gradients with greatly reduced errors

3 May 1999 – Oklahoma/Kansas tornado outbreak

Geo-I correctly captures important vertical moisture variations

GIFTS/GOES Retrieved-Moisture (g/kg) Errors

Truth>

Geo-I Errors>Standard Dev. = 0.9 g/kg

Note Geo-I reduces errors and captures

low-level moisture peaks and vertical

gradients

GOES Errors>Standard Dev. = 2.4 g/kg

GOES Sounder forFuture Mesoscale Models

• Future mesoscale models -- relocatable version down to 2 km resolution ~2006 to exploit budgeted new computer resources

• GOES will provide hourly data needed by 4-dimensional data assimilation and model system

• Will exploit achievements of NASA/NOAA Joint Center for Satellite Data Assimilation

Advanced GOES Sounder data in future, high-resolution mesoscale models will reduce weather watch areas

GOES-8 Winds Derived from Half-hourly Water Vapor ImageryDate: Oct. 7, 1995 Time: 1745 UTC

GOES interferometer data will yield increased number of vertical layers of wind representation

OSSE demonstrated improved capability of a geostationary interferometer for detailing

boundary layer moisture and deriving positive impact in near term forecast.

Significant Findings from Geo-Interferometer OSSE

Geo-Interferometer (Geo-I) sees into Boundary Layer (BL) providing low level (850 RH) moisture information; Geo-

Radiometer (Geo-R) only offers information above BL (700 RH)

OSSE 12 hr assimilation followed by 12 hr forecast

Soundings + Winds 850hPa RH Validation

25

30

35

40

45

50

55

0 2 4 6 8 10 12 14 16 18 20 22 24

Hour

S1 S

core

CONV

GEO-R

GEO-I

Soundings + Winds 700hPa RH Validation

30

35

40

45

50

0 2 4 6 8 10 12 14 16 18 20 22 24

Hour

S1 S

core

CONV

GEO-R

GEO-I

LEO VS. GEO 850hPa RH Validation

30

35

40

45

50

55

0 2 4 6 8 10 12 14 16 18 20 22 24

Hour

S1

Sco

re

CONV

LEO

GEO-I

Significant Findings from Geo-Interferometer OSSE

Two polar orbiting interferometers (Leo) do not provide the temporal coverage to sustain forecast improvement out to 12

hours. Only the hourly Geo-Interferometer (Geo-I) observations depict moisture changes well enough for forecast benefit.

OSSE 12 hr assimilation followed by 12 hr forecast

Summary -- ABS

The Advanced Baseline Sounder overcomes existing instrument limitations.

Geostationary interferometry will resolve high temporal and vertical fluctuations of moisture that are not resolved by current in-situ or satellite measurements.

Only geostationary interferometer observes critical meteorological parameters (temperature, moisture, clouds, winds) with necessary temporal, spatial and vertical resolutions to support future • Nowcasting, • Short-range weather forecasting, and • Longer-range numerical weather prediction.

The Advanced Baseline Sounder will provide required high spectral resolution measurements.

Expectations from the Geo-Interferometer

* depicts water vapor as never before by identifying small scale features of moisture vertically and horizontally in the atmosphere

* tracks atmospheric motions much better by discriminating more levels of motion and assigning heights more accurately

* characterizes life cycle of clouds (cradle to grave) and distinguish between ice and water cloud ( which is very useful for aircraft routing) and identify cloud particle sizes (useful for radiative effects of clouds)

* measures surface temperatures (land and sea) by accounting for emissivity effects (the improved SSTs would be useful for sea level altimetry applications)

* distinguishes atmospheric constituents with improved certainty; these include volcanic ash (useful for aircraft routing), ozone, and possibly methane plus others trace gases.