ASCII Soundings Binod Pokharel

Two ASCII-WWMPP sounding sites 72MGAUS soundings (ASCII) GPS-based soundings (GRAW) (1 sounding per RSE case) ASCII Window C only ASCII winds ( °)

MGAUS sounding site Battle Pass 43 km

Dixon Airport radiosonde launch site + weather station (10 m wind, 2m q, T, net radiation continuously op.) runway views from this spot Bridger Peak (38 km) Battle Mtn (13 km) Battle Town site (41 km) Sandstone ridge Red Mtn (38 km) Elkhead Range looking NE (downwind) looking south

How to use the 72 sondes? 72 units/15 IOPs = 4.8 sondes per IOP proposal: we do NOT use a sonde for case calling suggested distribution: type of IOP# IOPs*# sondesfirst sondefrequenc y double-flightup to hr after IOP start 1.5 hrs single-flightup to hr after IOP start 2 hrs blowing snow hr after IOP start 2 hrs * in the best-case scenario, we ‘ll need 74 sondes, that is 5*6 + 10*4 + 2*2 …

Radiosonde Training Training in Boulder with Tim Lim

Temperature Sensor Humidity Sensors GPS Antenna Battery Case Antenna GC25 Interface Vaisala Ground Check set (GC25) for radiosonde

Ready to Launch

key sounding parameters wind speed and direction at 700 mb temperature at 700 mb ST wind speed and direction LCL level (m) and LCL temperature ST Brunt-Väisälä frequency ST Richardson number temperature at the level of the generators ST=surface to mountain top level average } case calling parameters

sample sounding (test case in Boulder)

Sounding Parameters ParametersAltitude, mAltitude for ASCII Ground LCL N/A Mountain AgI GeneratorsAltitude, mT, o C Gen Gen Gen From Boulder Sounding, Key parameters summary Date: Time: Z Paremeters700 mbAverage (ST)LCL ( m) Wind Speed, m/s Wind Direction Temparature, o C ST N (s -1 ) ST Fr ST Ri ST: Average value is calculated from surface to mountain top LCL is calculated assuming lowest 50mb are well mixed Mean θ and mr are calculated in the lowest 50 mb Surface T and Td is computed from mean theta and mr LCL mb Stable as Ri>0.25 Flow blocked as Fr<1

challenges, limitations Cold and windy! If instrument does not work after balloon launch Need to launch another one immediately no data transmission when GPS signal is lost Some variables are available (pressure, Temperature, RH), but others are not (Wind, altitude..) Sounding plot is available after the balloon reach tropopause It takes about 90 minutes to reach tropopause Calculated parameter is not available immediately Temperature, wind speed, and wind direction at 700 mb can be available from the display plot when balloon is ascending, but difficult to get the actual wind values Data will be processed using some software to get the actual wind data

Plans Mock IOP at Dixon airport with Tim Lim during the week of 19 Dec 2 persons on site most of the time: – Binod Pokharel – Other one from U Illinois Time to prepare sonde ~ 1 hour Travel time from Savery to Dixon Airport ~10 min Have to be ready ~2 hours before first sonde

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