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Adaptative observations with balloons in Mediterranean

This article discusses adaptive observations using drifting platforms such as stratospheric and tropospheric balloons. It explores the use of these platforms in various research projects and highlights the benefits and challenges of adaptive observation techniques. The article also introduces new-generation aerostats and surface balloons.

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Adaptative observations with balloons in Mediterranean

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  1. Adaptative observations with balloons in Mediterranean C. Basdevant2, S. Bastin3, P. Drobinski2, P. Cocquerez4, C. Fesquet2, A. Doerenbecher1, P. Durand5, A. Hertzog2, F. Rabier1, A. Vargas4, N. Verdier4 1 Météo-France & CNRS (GAME), Toulouse, France 2 IPSL/LMD, Palaiseau, France 3 IPSL/SA, Paris France 4 CNES, Balloons Department, Toulouse, France 5 OMP/LA, Toulouse University, France

  2. Adaptive observation • Principle and techniques • Adapting drifting platforms • A stratospheric platform: the driftsonde • The VORCORE, AMMA and TPARC experience • What next ? • A tropospheric platform: the BLPB and Co. • AMMA and VASCO • The new generation of aerostat • A surface balloon: the Aéroclipper • Adaptive observation & strategies Plan

  3. Adaptive observation • “Observing practice” • Dedicated flexible observing network • Field experiments with upstream & downstream components • Use objective numerical techniques to compute the “targeting guidance” • Most advanced techniques predict expected reduction of forecast error variance • Use either adjoint or ensemble based computat°s • Many implementations (FASTEX’97 to PREVIEW’08)

  4. Adjoint computations and sensitive areas Routine RS at 18 UT Extra RS out of the sensitive area Extra existing RS Extra simulated RS verification area KFS Kalman Filter Sensitivity

  5. Adaptive observation and drifting platforms Platform control • Adaptive observation assumes that the location of additional observing platforms can be predicted, i.e. the platforms are fully controlled. • The control of the trajectory of drifting balloons is verylimited. • Supposing a prefect trajectory model, the place and the time of launch are the main parameters that control the trajectory (with a known and fixed flight level). Accounting for the observation impact of the drifting platform • Need to interface back-trajectory tools and targeting guidance computation tools. • Importance of high quality prediction of the back-trajectories as they add uncertainty in an uncertainty estimate. • Definition of a target to be hit by the platform as the numerical tools do not yet account for multi-assimilation-cycle data impacts (i.e. all the data collected along the trajectory).

  6. Which drifting platform ? • A stratospheric platform: the driftsonde • The VORCORE, AMMA and TPARC experience • What next ? • A tropospheric platform: the BLPB and Co. • AMMA and VASCO • The new generation of aerostat • A surface balloon: the Aéroclipper

  7. Balloons at CNES

  8. “Cost-effective dropsonde observations of wind, temperature, and humidity to fill critical gaps in coverage over oceanic and remote artic and continental regions over days to weeks”. Driftsondes (AMMA & T-PARC)

  9. The trajectories of driftsondes exhibit stratospheric waves that are not well represented in the atmospheric model fields. The deployment was a success. 8 missions up to 18 days long. The data were on the GTS. Drifstondes in AMMA (2006) prediction from previous years

  10. VORCORE 2005: stratospheric balloons in the polar vortex Sep. – Oct. 2005 Dec. 2005 – Feb. 2006 CONCORDIASI: 12 units (in 2010). Nov. 2005 Driftsondes over Antarctica (2010) Trajectories for late winter/ early spring (Austral). 27 units. Balloons are kept in the vicinity of the pole for several days

  11. Simulated stratospheric trajectories using ECMWF analyses at 100 hPa (2001 data). St-Johns Boston Virginia Beach Jacksonville Miami • The southern the launch site, the least Europe reaching balloons. • The mean arrival latitude is 40°N (i.e. Mediterranean), range is 20°N-60°N. • The mean duration is 5 to 8 days, with higher variability in the North. Driftsondes over the Atlantic ? Courtesy: C. Fesquet, C. Basdevant & P. Drobinski

  12. Drifting at low level… • A tropospheric platform: the BLPB and Co. • AMMA and VASCO • The new generation of aerostat • A surface balloon: the Aéroclipper

  13. Meso-NH back-trajectories CAPE and back-trajectories computed with Meso-NH (10km) on the Aude case (November 1999). The air particles are initiated on the 13/11 at 00UT, the initial locations are shown 6 hours earlier: 12 Nov. at 18UT (CAPE fieldset validity). Published in Quarterly Journal of the Royal Meteorol. Soc., 2008, #134, pages 111-130 Nuissier, O., V. Ducrocq , D. Ricard , C. Lebeaupin & S. Anquetin: A Numerical Study of Three Catastrophic Precipitating Events over Southern France. Part I: Numerical framework and synoptic ingredients.

  14. A few figures… Lifetime: 1 month Flight level: 1500 m Envelope’s weight: 3.5 kg Envelope’s volume: 8 m3 Instruments’ weight: 2.5 kg Instruments: P, T, Humidity & GPS Boundary Layer Pressurized Balloons (BLPBs) Humidity Temperature Pression GPS+ARGOS

  15. www.lmd.ens.fr/ammabp BLPBs in AMMA (2006) Observed trajectory of BLPB#8 and predictions on various pressure levels. Colours show the 24h trajectories starting from observed position every 6 hours. ECMWF analyses are interpolated to compute the trajectories. mountains ITF cycloid conv. sys.

  16. BLPBs and VASCO (2007) 1/2 VASCO campaign (Seychelles) Typical trajectory Temperature measurements www.lmd.ens.fr/tromeur/VASCO/Journal_2007.html

  17. BLPB #9 is caught by the cyclone Gamède. BLPB #8 flew to Antarctica. BLPB #9 Gamède (2007/02/21 to 2007/03/04) BLPBs and VASCO (2007) 2/2 • The lifetime of the BLPB is long : several months. • The sensors remain fragile: new protections should be designed. • Data availability should increase up to 90% of the balloon lifetime • High freq. sampling during ascents (1-4mn), low freq. in floatation (10-20mn) • Data should be smoothed (10s, 1mn, 20mn)

  18. During AMMA (2006), flight termination was due to precipitations (6 units), too low flight level (2), orography (3) and updrafts (convection) (4 units). Prediction of the trajectories A double envelope forbuoyancy control • ECMWF analyses: • Correct up to 96 hours • Need to work with HR vertical levels • Better results by daytime • What about ECWMF forecasts ? Need tocontrol the flight(not isopicnal) The new generation… New sat’ com’ system: IRIDIUM New sensors (robustness, new parameters) Slightly larger envelope Flight control and new safety systems BLPBs A qualification unit of the new BLPB platform now exists and should be operational by the end of the year.

  19. Courtesy: C. Basdevant • Duration of flights above sea is short : • Mean duration ~ 3 days !!! • Several launching sites are tested: • Balearic Islands, • Sardinia, • Gibraltar. • Several meteorological situations: • Floods in the Gard (Sep. 2002), • Storms in the Balearic Islands, • Algeria, Morocco (Nov. 2001) BLPB trajectories in the Mediterranean Trajectories of 50 balloons released from Alghero in the Northwest of Sardinia on 9th Nov. 2001: balloons are released every 2 hours & fly at 850 hPa in ECMWF analyses.

  20. BABA = Law Altitude Balloon BLPBs • Small, cheap & short life cigar-like balloons • P, T, Humidity & GPS • Use of radio com’: limited range • Deployed in ESCOMPTE (2001) • Small scale exploration. • Long life spherical balloons • P, T, Humidity, GPS & more… • Use of satellite com’: unlimited range • Deployed in many campaigns (2001) • Meso to Synoptic scale exploration. A network of balloons • Increased balloon lifetime • Radio collaboration/relay increase the useful range. Network of small balloons

  21. Measurement of ocean surface fluxes • Evaporation is crucial • Indirect (computation) in HyMeX • Smaller & easier platform ? Aéroclipper (VASCO 2006 & 2007) Duvel et al., Jan. 2009: The Aéroclipper, Bull Amer. Met. Soc.  “Evaporation is the process by which the air masses charge moisture during its passage over the Mediterranean.” 

  22. 3 observing levels tana td tobs tobs tvf Routine Observing System Decision Decision Adapted observation 850 hPa 950 hPa analysis  initial forecast  ? ?

  23. Targeting tools for balloons in HyMeX • Trajectography tools to be interfaced with “classical” targeting guidance. • Development of a mesoscale targeting tool applied to the deployment of BLPBs • Management of synoptic scale sensitive areas to guide driftsondes’ deployment. Link with other observing campaigns • Driftsondes may be of interest for both HyMeX and T-NAWDEX. A collaborative effort would be welcome as the matter is difficult (cf. safety, ATC, etc.) • Sensors for fluxes as well as aerosols/chemistry are envisaged on the BLPBs (Charmex). Observing strategy and predictability issue • The deployment of additional observations upstream of the experimental area would help constraining prediction errors inside that domain. • The adaptive observation should consider some “observing train” with decreasing scale and lead-time prior to the focused meteorological event. • The observation all around western Med. basin implies collaborations with North Africa. Concluding remarks

  24. Thank you !Questions are welcome.

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