DANO, Burkina Faso. Instruments Data set Status Highlights. Norbert Kalthoff and Juliane Schwendike. Institut für Meteorologie und Klimaforschung

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1 DANO, Burkina Faso Instruments Data set Status Highlights by Norbert Kalthoff and Juliane Schwendike

2 Dano (super-)site in Burkina Faso Dreyer Foundation Dano Dano Bontioli

3 Measurements at Bontioli site 2 Energy balance station (agricultural used area* and natural vegetation**) I * IMK-TRO, ** IMK-IFU Radiation balance Energy balance Soil temperature meteorol. parameters

4 Soil Moisture Measurements 1 km line Energy balance site 2 m 2 m 3 m -5 cm Sisomop Georadar TDR -1 cm TDR Sisomop Georadar -2 cm -5 cm -1 m -1 m

5 Dano site: Vertical soundings of PBL-conditions and during MCS events SODAR (continuous wind speed profiles) Radiosondes (used for data assimilation by ECMWF) Before a MCS and during a MCS passage

6 Events during SOPs SOP Date Events radiosondes SOP1-a 1 June 26 2 June 26 3 June 26 4 June 26 5 June 26 MCS1 (MCC) 5 6 June 26 7 June 26 MCS2 (MCC) 5 8 June 26 9 June 26 1 June June 26 MCS3 (MCC) 5 12 June June June June June 26 Total # of sondes: 94 SOP Date Events radio sondes SOP2-a2 17 July July July 26 2 July July July July July July 26 MCS4 (MCC) 4 26 July July July July 26 3 July July 26 MCS5 (Squall Line) 6 1 August 26 2 August 26 3 August 26 shallow convection 4 4 August 26 5 August 26 6 August 26 deep convection 4 7 August 26 deep convection 3 8 August 26 9 August 26 1 August August 26 MCS6 (Squall Line) 6 12 August August 26 moderate convection 4 14 August 26 MCS7 (Squall Line) 6 15 August 26 moderate convection 4 16 August August August 26 MCS8 (Squall Line) 3 19 August 26

7 Results from soil moisture, energy balance and PBL measurements in session: Land-surface processes (Wednesday) Surface-atmosphere feedbacks (Friday) volumetric water content in m 3 m August 26 7 August 26 Soil moisture variability on a 1 km scale measured by a Georadar distance in m Results from MCS events: now

8 MCC on MCS on 11 June 26 Passing the Dano site, Burkina Faso

9 MCS tracking on 11 June 26 Dano 1. Radiosonde 2. Sonde 3. Sonde 4. Sonde 5. Sonde 9 UTC 2 UTC UTC 7 UTC 16 UTC Image courtesy of Météo France. yellow contour when the system is detected for the first time ("triggering" of the system), red contour when the system is growing, violet contour when the system is mature, blue contour when the system is decreasing,

10 Accumulated Rainfall from TRMM Heavy precipitation in the region around Dano maximum values at about 1.6 N, 1.5 W Dano

Vertical velocity (Pa/s) and wind speed (m/s) 12 UTC 18 UTC x 7 hpa AEJ is dominating the

11 Environmental conditions Relative humidity (%) and wind speed (m/s) 12 UTC 18 UTC x 1 hpa An AEW trough moves over Burkina Faso Moist air in the south Dry air in the north Vertical velocity (Pa/s) and wind speed (m/s) 12 UTC 18 UTC x 7 hpa AEJ is dominating the flow pattern Trough axis is located at about 1-2 W The jet axis at approx N X: Dano site

12 Radio soundings Prae-MCC condition: From the surface up to 2 km ASL: wind from S/SW PBL capped by inversion and a decline in humidity above At ~5-6 km: second elevated inversion, accompanied by another decline in humidity AEJ maximum at about hpa below the elevated inversion

13 Radio soundings Convective region: Temperature decrease is restricted to the CBL Maximum wind veering at the top of the gust-front layer Low level jet dominates the wind profile AEJ structure is weak Convective region is dominated by vertical motion

14 Relative Ascent Speed (RAS) The RAS of the radio sounding on 11 June 26 at 2 UTC at Dano site z in m ASL m s -1 Upper cloud layer (3-6 km) Lower cloud layer ( km) RAS in m s -1

15 Radio soundings Stratiform region: Near-surface wind turns towards S/SE AEJ strengthens (17-2 m s -1 ) and LLJ is reduced (12-15 m s -1 ) Atmosphere is very dry from the top of the surface layer up to about 4.5 km Post- MCC conditions: Winds in PBL from S Strong wind veering and wind shear between PBL flow and AEJ are re-established Humidity in the PBL is still low

16 Near-surface meteorological parameters at Bontioli G: global radiation P: pressure v h : horizontal wind speed wd: wind direction PinhPa UTC v in m s h v h wd UTC P G Gust front Gust front wd in gedree GinWm -2 Tin C σ in m s T 2 RH UTC 3 1 σ u 9 σ v 8 2 NN UTC T: temperature RH: relative humidity RH in % σ u, σ v : standard deviation NN: precipitation NN in mm

17 SODAR measurmenst at Dano db 2 ms -1 Wind veering from W to E in PBL zinmagl wind speed values before and after the gust front: 1-17 m s UTC Gust front

18 Final comments Conditions on 11 June are representative for several observed MCC passages in Dano Data will be used for LM model simulations Impressions of an MCC passage

Numerical modelling of the interaction of soil moisture with planetary boundary layer features and convection over West Africa

Numerical modelling of the interaction of soil moisture with planetary boundary layer features and convection over West Africa Leonhard Gantner, Norbert Kalthoff, and Martin Kohler Photo: J. Schwendike