IHOP Radiosonde and Dropsonde Data: Highlights and Problems Radiosonde data Summary Humidity sensors Problems Dropsonde data Scientific Highlights Junhong (June) Wang Kate Beierle NCAR/ATD This talk is about IHOP dropsonde data. I will first give you an overview … Performances focus on the dry bias and the performance inside clouds I would acknowledge my co-author, kate and other …

Summary of all radiosonde data from IHOP Radiosonde Systems Number of soundings Radiosonde Types Sites Time (UTC) NWS 1653 (410) Vaisala RS80-H & VIZ 14 00 and 12 UTC every day, 11 IOPs at 15, 18 21 UTC, and 4 IOPS at 18, 21, 03 UTC ARM 862 Vaisala RS90 5 (C1, B1, B4, B5, B6) 02, 05, 08, 11, 14, 17, 20, 23 UTC ISS 138 Vaisala RS80-H Homestead 18 UTC every day, and various times for IOPs Ref. Sonde 16 Ref/RS80H/VIZ 18 UTC and others Mobile_CLASS 60 RS80-H mobile various Mobile_GLASS1 74 Mobile_GLASS2 77 Total 2625 3 types  19 + 3 mobile   Various Check these number???? Here is a summary of all radiosonde data collected from IHOP. It includes soundings at 13 NWS radiosonde stations, 5 ARM stations, one ATD ISS at Homestead, and three mobile sounding systems. Total …

Reference sonde Two NWS stations (DDC and Alb.) launch VIZ sondes, and others use Vaisala sondes.

Radiosondes Reference radiosonde VIZ B-2 Vaisala RS80-H 400MHz transmitter GPS receiver Swiss Radiosonde C34 SW chilled-mirror DP hygrometer – reference humidity sensor Carbon hygristor Copper-constantan thermocouple Hypsometer Vaisala RS80 NWS VIZ B-2 Reference radiosonde RS90 (~1993): Smaller THERMOCAP Heated twin F-HUMICAP VIZ-B2: Rod thermistor Carbon hygristor Vaisala RS80-H VIZ B-2 RS80-H (~1990): THERMOCAP F-HUMICAP Vaisala radiosondes are used in ~51% of global radiosonde stations, so it is necessary to say a little bit about it. RS80 still used in most of stations has two types .. 40s heating, then 100 s measuring

SnowWhite Chilled-mirror dewpoint hygrometer Scattering light detector Heated sensor housing Reflecting light detector Thermocouple Mirror Let me first explain how the SW measures humidity. Here is the picture of SW, including electronics, batteries, sensor housing and electrical heat pump. Here is a schematic plot showing how SW measures humidity. SW is based on physically well-known chilled-mirror principle. A mirror is mounted on the cold side of a Peltier. The system maintains a frost layer on the mirror all the time. The mirror T is DPT. One of advantages with SW is that it can detect clouds and possibly total liquid/ice water content. I will show you some results latter. The sensor housing is heated. The air sample containing water or ice particles is warmed up by heated housing. All droplets are evaporated, causing a measurement of super-saturation. Fast response No influences of radiation, wind and others Peltier Accurate measurement of dew/frost point Detects clouds and measures their liquid/solid water Needs no individual calibration and recalibration after recovered

Data quality control for ATD Radiosonde Data 1. In-field data processing 2. ASPEN 3. Individual Skew-T examination SAH during IHOP is due to the fact that the aspirator used for collecting prelaunch data was not shaded from direct sunlight during IHoP and it draws the air from the surface. SAH: 40-60 s (200-300m) for RH, negligible for T Pick up one sounding showing the SAH error??? (extreme??) In-field data processing: (Ned’s software) Outliner removing (mainly remove transmission error) Low-pass filtering to remove balloon swinging Interpolate all data to the same time scale: 1s Filling small data gaps (< 30s) Transmission errors: operator’s error (tuning frequency to keep tracking balloon, atmospheric noise, equipment failure) ASPEN’s QC procedures include: limit check, satellite check (dropsonde), buddy check, outlier check, filter check, monotonic pressure check, vertical velocity check (dropsonde) 4. Comparisons of prelaunch and surface data 5. Comparisons with other data

Aspirator upgrade for ISS New Old The new aspirator has much more air to the sensor and better air flow, draw the air horizontally, has a stable holder for the sonde for easy launch under strong wind condition and has a smaller and folding table for both fixed and mobile sounding system.

Summary of all dropsonde data from IHOP PTU/W profiles Validation for newer WV instruments Missions Falcon Lear Total BLH 19 17 36 M LLJ 62 93 155 CI 7 169 176 E LLJ 53 88 332 420 The dropsonde was mainly used to provide PTU/W profiles and for validating other new WV instruments, such as DIAL. Launched from Falcon and Lear for four types of missions, … and with different flight patterns for different missions, such as box flight patterns for MLLJ Total 420 dropsondes were launched. Lear launched much more than Falcon. CI and MLLJ missions used most of dropsondes

NCAR GPS Dropsonde Here is our GPS dropsonde (~400 g). The dropsonde is dropped from research aircrafts over remote areas such as the oceans, polar regions and sparsely inhabited land masses. It descends through the atmosphere on a parachute to measure PTU and wind profiles. Here is a detail picture of the sonde, including a 4-channel transmitter, so you can have four sondes in the air at the same time. Dropsonde data during hurricane flights have improved the accuracy of forecasts of hurricane landfall by about 20% over the decade of the 1990s. Currently the system is installed … We also completed our automatic dropsonde system about two years ago. It stores 16 dropsondes in a pot, which is installed below aircrafts. You don’t need operators in the aircraft. All pilots need to do is to push a button for starting releasing sondes. Next I am going to give you a couple of dropsonde data highlights.

Large parachute Small parachute Here are % of good points for all Lear dropsondes for T (black), RH (red) and winds (green). On average, T and RH have ~90% good points, but 50% for winds. You see smaller percentages before June 5. I think it is due to the small parachute used before June 5, but the large one afterwards, ask Terry?? Next I am going to use data from two missions to show you some scientific highlights. Large parachute Small parachute

MLLJ on June 9 (1200-1930 UTC) Box flight path (clockwise) Clear sky in the domain LLJ on the northern leg Lear: 48 (took off from NW corner, ~50 km, two box flights) Falcon: 21 (took off from SE corner, ~50 km) Mapping moisture and intercomparison with DIAL, LASE, NAST Here is a MLLJ mission on June 9 Both Lear and Falcon flied boxes. … Let’s look at dropsonde winds along this line from E-W from both lear (red) and falcon (black). You see maximum speed reaching 30m/s Next let’s look at T/RH variations along the box from lear dropsondes from two box flights

T/RH variations for two Lear box flights June 9 East-west Terrain change T differences for two flights: T warmer up by several degrees from the first to the second flights RH shows larger W-E (or longitudinal) variations: BL getting moister form W to E and topped by a shallow dry layer. Another moist layer is developed around 650 mb. Similar features shown in the second flights but with smaller magnitudes. Next I am going to show you detail structure in this W-E leg. RH variations within each box (stronger E-W variations) RF9 RF10

MLLJ (East-West on the Northern Leg on June 9) Inversion-capped moist layer Two-layer moisture Specific Humidity (g/kg) DIAL on Falcon The location of the dryline (dramatic increasing of surface Q by > 5g/kg)? Inversion-capped moist layer, increasing in depth eastward Two-layer moisture structure near NE corner

CI on June 12 (1900-2200 UTC) Plot color filling to see why there is a minimum for 2102 UTC??? Replot the plot to change 6/09 to 6/12 and put vertical line on CAPE/CIN fig. Development of moist layer around 500 mb High CAPEs and near-zero CINs in all soundings in the second flight (Development of convection)??

Performance in Clouds CI May 22 22:14-22:39 UT Dry Line Look at CAPE, CIN and LCL (cloud base?), how ARM CF lidar/radar data? Here is a CI mission on May 22. 8 dropsondes were dropped along this line. Corresponding T/RH/Q profiles are shown here. Red lines are RH. Perpal lines show 90% RH lines Satellite data show Wave clouds >90% RH, strong T inversion above cloud top, Last four show very similar structures but RHs in moist layers can vary from 90% to 100%. Also notice the development of second moist layer from 3-4 km. I show you this sounding before with comparison with RS90 data at CF. very good agreement This is consistent with what we found from Dycoms-II data.

Data quality control for ATD Dropsonde Data ASPEN (limit, buddy, outlier, filter, etc.) 2. Individual Skew-T examination 3. Histograms of PTU and wind 4. Time series of PTU and wind 5. Comparisons with other data Pick up one example

Geopotential height problems and solutions Before After Integrate from flight-level down Unknown surface altitude 1. No flight-level PTU data 2. Use flight-level height but 1st available pressure (~20s) ~200-300 m overestimate of heights 1. Problems: 2. Corrections: Good soundings Integrate from surface up Surface elevation Soundings with missing data above surface from FL down Add PTU to FL Corrected heights

Geo-potential height data after corrections Missing data before landing

Importance Notes for IHOP radiosonde/dropsonde data Do not use reference sonde pressure and wind data: The reference sonde (RS) uses a hypsometer to measure pressure. Unfortunately the hypsometer was not stable and has all kinds of problems. We didn't correct balloon swing at all for winds and had quite big balloon swing because of bigger balloons used. Sensor arm heating error in radiosonde data at Homestead: The SAH error depends on a lot of factors Different impacts for T and RH: 40-60 s (200-300m) for RH, negligible for T. Take precautious about dropsonde geopotential data: The Geopotential height problems in IHOP dropsonde data are investigated and corrected. But there may be some un-identified problems in some individual soudnings. Errors/Biases and Error variances in radiosonde and dropsonde data will show latter