The RADAGAST project

Tony SlingoEnvironmental Systems Science Centre

University of Reading

• Background and motivation

• Aims

• Methodology

GIST 23, Deutscher Wetterdienst, 27-29 April 2005

Atmospheric radiation balance

• Top of atmosphere fluxes are well observed– Nimbus 7, ERBE, CERES and of course GERB

• Surface fluxes less well observed– due to variable quality and sparse distribution– GEBA and BSRN projects (ETH Zurich)

• So, the atmospheric radiation balance is not well constrained– e.g. solar absorption from 67 to 93 Wm-2

– similar disagreements in the thermal region– important: relevance to hydrological cycle

Atmospheric radiation balance

• Major disagreements about the magnitude of solar absorption by clouds, aerosols and gases

• Attempts to resolve these disagreements have been beset by sampling problems– limited global distribution of surface sites and limited

instrumentation at most sites– limited spatial and temporal sampling by in situ

experiments using aircraft– limited spatial, temporal and/or spectral sampling by

satellites above surface sites

• We therefore need:– a well-instrumented surface site visible from GERB

Current ARM sites

Cut-away schematic

The AMF is currently at Point Reyes, California, on

its first deployment

The ARM Mobile Facility (AMF)

Radiometric

Atmospheric Emitted Radiance Interferometer (AERI)

Ground Radiometers on Stand for Upwelling Radiation

(GNDRAD)

Infrared Thermometer (IRT)

Multifilter Rotating Shadowband Radiometer (MFRSR)

Microwave Radiometer (MWR)

Sky Radiometers on Stand for Downwelling Radiation

(SKYRAD)

Cloud Properties

Millimeter-Wavelength Cloud Radar (MMCR)

Micropulse Lidar (MPL)

Microwave Radiometer (MWR)

Total Sky Imager (TSI)

Vaisala Ceilometer (VCEIL)

Surface Meteorology

Surface Meteorological Instruments for TWP (SMET)

Atmospheric Profiling

Atmospheric Emitted Radiance Interferometer (AERI)

Balloon-Borne Sounding System (SONDE)

Surface Energy Flux

Eddy Correlation Systems (ECOR)

Infrared Thermometer (IRT)

Aerosols

Multifilter Rotating Shadowband Radiometer (MFRSR)

ARM Mobile Facility: instruments

AMMA: 2006

AMMA also includes DABEX (Dust And Biomass EXperiment), at the beginning of 2006

BAE 146-301 Large Atmospheric Research Aircraft G-LUXE

Meteosat Second Generation

the latest operational European weather

satellite, the first of which was launched in August 2002 as

Meteosat 8

• Radiative Atmospheric Divergence using ARM Mobile Facility, GERB data and AMMA stations

• A proposal led by Tony Slingo to deploy the new ARM Mobile Facility in Niamey, Niger to coordinate with AMMA 2006 and link to GERB

• Approved in October 2005 by the ARM project– this is a substantial commitment and provides a great

opportunity for ARM, GERB and AMMA– links to NCEP, ECMWF and Met Office

RADAGAST

RADAGAST

• Aim: derive consistent profiles of atmospheric structure and heating rates for a wide range of clear, cloudy and aerosol conditions, together with radiative fluxes at the top of atmosphere and at the surface

• Method: combine data from GERB and other satellite data, ARM (surface) and AMMA (in situ)

Outgoing longwave radiation from the ARCH product, at a resolution of about 10km, at 1200UT on 24 July 2004. Values range from 100 Wm-2 (gray) to 350 Wm-2 (dark red). The dot shows the location of Niamey.

MODIS Products

Reflectivity

Emissivity8.6 mBand 29

SPOT images of the region around Niamey. The June image has some high cloud. The full image is about 60km on a side, similar to the 40-50km resolution of GERB.

N24-June.gif

Outline of joint proposal to DOEfrom ESSC and PNNL

• Acquire data from AMF, sondes, aircraft etc to characterise the atmospheric structure

• Acquire data from GERB, SEVIRI and other high resolution satellite data to characterise the radiative fluxes at the TOA and surface

• Merge the satellite and surface radiative fluxes• Adjust atmospheric structure for consistency with radiative fluxes• Calculate radiative divergences and heating rates• Create test cases for evaluating models over a wide range of

conditions (clear, cloudy, aerosol atmospheres)• Evaluate NWP models from NCEP, ECMWF and Met Office• Display project results on a real-time web page

Average vertical profiles of all-sky minus clear-sky heating rate profiles, showing the effect of clouds on the heating rates, for Feb-March 2000 at the ARM site at Manus from a) calculations based on the ARM measurements, b) heating rates produced by the MMF, and c) heating rates produced by the CAM 3.0 model.

Summary

• The deployment of the new ARM Mobile Facility (AMF) to Niamey, Niger during 2006 will provide a unique opportunity to bring together ARM, GERB and AMMA and to provide new datasets for evaluating models over a wide range of atmospheric conditions

• NCEP, ECMWF and Met Office are project partners• Additional opportunities for interacting with CERES

and for evaluating surface radiation budget derived from satellite data