Development of a GNSS Ground-Based

Meteorological Network in Amazonia

David K. Adams, Rui Fernandes, Jair Maia, Robert

Kursinski, Luiz Sapucci

OUTLINE

Water Vapor in Tropics

GNSS Meteororology

PWV/Convective Events:

Preliminary Obs.

Development of Dense

Network

General/Specific Goals of

the Network

Water Vapor in Tropical Deep Convective Regime

• The distribution of water vapor is highly variable and is not dynamically linked with temperature and pressure.

• Vertical distribution of water vapor critical in atmospheric stability in deep convective regimes.

• Complex role in organization and propagation of convective events (difficult to parameterize)

Observations of Water Vapor -a problem

• In deep tropics few in situ observation, sparsely located, infrequently sampled (e.g., radiosonde)

• Satellite platforms using IR may have probems in

calculating PWV in cloudy rainy weather

• Microwave sounder on Satellites, all weather, but may

suffer from instrument drift.

• GNSS satellite system may provide all weather PWV and

vertical profiles.

ATMOSPHERIC DELAY OF GPS SIGNALS IS THE BASIS OF GNSS METEOROLOGY

GPS Station (INPA), Manaus, Brazil.

NOAA/GSD Real Time GPS-MET

http://gpsmet.noaa.gov/test/cgi-bin/gnuplots/rti.cgi

GPS Antenna and MeteorologicalWeather Transmitter (Pressure,Temperature, Wind, RelativeHumidity, Rainfall)

Initial Dense Network Research (Minimum Separation Distance)

• ~ 2.4 km scale height

of wv

• Receiver “Cone”

Diameter ~ 10km

• Determines mimimum

spacing between

stations for PWV

(integrated value)

Tendencies and Small-scale Structurein PWV

• irregular spacing

(necessity)

• internet (a few)

• communication by

radio (expensive)

Logistics Problematic!GNSS Receiver on Swaying Tower?

• Non-Ideal GNSS Platform– Horizontal/Vertical motions

– Possible Multipath Interference

– Emitting Radio Antenna on tower

– Yet Very Good Results

Water Vapor AdvectionMultiple stations- PWV weighted winds

Dense Network in Manaus

~ 20 receivers with met. stations

Difficult Logistically

Irregular spacing (necessity)

Internet

(few stations)

Communication by radio

Observational Capability5-10km separation

5 to 10 min. PWV data

1 minute surface weather data

Twice-daily Sondes

S-Band Doppler Radar

GOES 12 (near Zenith, 15

min.)

Hydrometeorolgical

Network/Flux Tower

General Goals for Ground-Based GNSS in the Amazon

• Development of GNSS network throughout Brazil (Icaro Vitorello, INPE)

• Development of GNSS meteorology and Data Assimilation of

products (Luiz Sapucci, CPTEC, Joao Galera, UNESP)

• Development of Data Processing techniques (Rui Fernandes,

UBI, Joao Galera, UNESP)

• GPM-CHUVA Campaign in Manaus, late 2011 (Luiz

Machado, CPTEC)

• Water Vapor/Deep Convection studies (Rob Kursinski, UofA

and Dave Adams, UEA)

Water Vapor/Convection Studies

• Examine Deep Convection/Water Vapor relationship at scale appropriate for mesoscale organization.

• Role of Cold Pools in convective organization (Tompkins

2001a,b and Khairoutdinov and Randall 2006)

• Closure of the hydrological cycle (CHUVA) during

convective events

Expectations for the Network

• Functioning early 2011

• Planned for 1 year (capture seasonal cycle)

• Real-time data transfer and assimilation

• Generate convective climatology (e.g. role of cold pools)

• 3D water vapor fields (using slant path analysis)

• Datasets for initializing, constraining or verifying high

resolution models

Special Thanks to:

Icaro Vitorello - INPE

Antonio Manzi - INPA/LBA

Micrometeorology Group- INPA/LBA

Jorg Ohly - UEA

and You for attending.

dave.k.adams@gmail.com