COSMIC Retreat 2008 Caribbean Project Ground-based GPS Research Group

Ground-based GPS Network CONUS network Caribbean network

Impact of GPS PWV on Dean hurricane intensity forecast Continuous and real-time GPS observation help hurricane intensity forecast 6 hour DA window No DA One time DA Continuous DA Reference (true) forecast No DA One timeContinuous 991 hPa 977 hPa  Ps 3hPa  Ps 17hPa  PWV

Key observation for Dean forecast PWV observation near hurricane center PWV at Jamaica station

Negative correlation between pressure and PWV –Pressure sensor is important in GPS stations PWV exceed 75 mm in rradius of 150km from hurricane center –Grid GPS distribution with 1 degree is enough to detect higer PWV ? Surface pressure and PWV along latitude line of hurricane Dean MMM nesting 3 MMM nesting 2 MMM nesting 1 MMM nesting 3 MMM nesting 2 MMM nesting 1 80 mm 70 mm PWV SLP PWV >75 mm Suggestion from High-resolution Forecast

Background Error Statistics Snapshot of analysis increments (A-B) in PWV (top, 2D) and Qv (bottom, latitude-height cross section) NMC 10ays of

Dean Forecst

D cloud water D rain water D water vapor D temperature + D wind 0 min16 min32 min 48 min 600 km Temporal Evoluation of Phase Change of Water

1 hour Integration Water vapor Latent heat Intensification of hurricane D cloud waterD rain water D water vapor D temperature + v, w wind 600 km

Release of Latent Heat Phase change of water vapor for 60 minites Only one staion Japaica PWV data is assimilated Available latent heat Water vapor Rain water Cloud water

Consumption of Water Vapor Structure of PWV provided from Jamaica station changes its spatial distribution rapidly 0 min 32 min 60 min

Energy Blance in Hurricane 21:00 Jamaica station provides equivalent latent heat of 2.2 x J from positive increment of water vapor. M 8.5 earthquake: 3.6 x J Atomic bomb: 8.0 x J, Hydrogen bomb: 4.0 x J J/sec ? J/sec Release of latent heat from phase change of water (water vapor to liquid water) Friction J Kinetic Energy Data missing

OSSE Study and OSE STudy Consistent results with true data assimilation (1 deg. Grid, 1 point DA, etc) IC: _18

Real-time DA System O-B statistics, 1 day forecast, Case study

Hurricane and Tropical Storm in cases were reported from National Hurricane Center (NHC) by Oct. 9

Target Hurricane in Forecast Domain Hurricanes and tropical storms passed over Caribbean Network

Case Study for Gustav Will verify relative importnace of GPS PWV and COSMIC refractivity for 2008 hurricane track and intensity forecast

Forecast Validation with Met Observation Three typhoons have landfalled in Taiwan in 2008

Summary and Discussions GPS PWV can improve hurricane intensity forecast if it can observe PWV near hurricane center Cycling 3DVAR DA can get maximum benefit of continuous real-time GPS PWV observation Combined use with COSMIC; Issues to be verified –Relative importance of GPS PWV and COSMIC –Track and Intensity –Additional benefit of those against conventional data Optimal observation from Ocean (moving) platforms Encourage to put ZTD/PWV from IGS near real-time stations to GTS like COSMIC refractivity