OWP: Radiosondes and profilers Doug Parker, CEH Wallingford, 21 January 2005

Why are the radiosondes needed? Data assimilation –Detailed (sustainable) analysis of weather and climate –Data impact studies Is the existing network sufficient to analyse the atmosphere ? Adrian Tompkins (ECMWF)

ECMWF data impacts (Tompkins et al 2005) All data are about equally useful, but –Radiosondes are most important at lower levels (below ~ 600 hPa ~ 16,000 ft) –Radiosonde thermodynamics are more important than all wind data

Why are the radiosondes needed? SOP objectives for radiosonde data High resolution analysis of weather systems –Coordinated with radar, aircraft … –Diurnal cycle  high frequency Water and energy budgets Assimilation into regional models - Regional NWP Security of aviation

‘AMMA’ network ASECNA New stations Non-ASECNA Not reporting

Quadrilaterals - fluxes

Sounding frequencies on these networks EOP/LOP: As a minimum: –March 2005 – October 2007: 1 per day –March 2006 – October 2006: 1 more per day –Total: 1220 per station (~ 20,000 soundings) –Extra: 6350 sondes contributed by AMMA-IP SOP: Depends on operations – –Could be 8 per day; –Could make use of descent data –Plan for 4600 additional soundings

AMMA RS projects: AMMA-EU 2 MEu (includes Infrastructure) France - limited money for upgrade and about 1000 soundings (EOP) UK - about 880 soundings (EOP/SOP). US - seeks funds for –SOP soundings (about 1000) –2 ISS deployments (SOP) –Conakry + sondes (EOP/SOP) These are relatively small-scale!

Other AMMA RS activities: Monitoring of data transmission and receipt (data collectors  ECMWF) Monitoring PILOT network Archiving high resolution data Strategy and implementation for long-term support

AMMA Radiosonde Group Formed mid-2003 Objectives: –to formulate strategy for radiosonde deployment and –to assist in liaison between data providers and data users

AMMA-UK radiosondes Budget incorporated in ‘Global’ AMMA RS budget Purchasing through ASECNA – lower prices We are buying priorities in the deployment! –To support the northern region (one station at higher frequency) –To support the BAe146

Tethered balloon system Carries a turbulence sonde Ceiling ~ 2 km To be deployed June to September 2006

3 sodars To be deployed in one of the surface flux mesosites (probably around Niamey) June to September 2006

Sodar specifications Thickness of layer m Lowest measurement height 20 m Maximum range m Averaging time 1 min to 60 min (typically 10 min) Accuracy of Horizontal Wind speed m/s Accuracy of vertical Wind speed m/s Accuracy of wind Direction 2 - 3° Measurement range horizontal - 50 m/s to +50 m/s Measurement range vertical -10 m/s to +10 m/s Operational temperature range -35 to 50 °C