The 2015 Enhanced Soundings for Local Coupling Studies Campaign at ARM-SGP

Description

The DOE- ARM Enhanced Soundings for Local Coupling Studies Field Campaign (ESLCS) took place at ARM’s Southern Great Plains (SGP) Central Facility (CF) between June 15 and August 31, 2015. During ESLCS, routine 4-times-daily radiosonde measurements at the ARM-SGP CF were augmented on 12 days (June 18 and 29; July 11, 14, 19, and 26; August 15, 16, 21, 25, 26, and 27) with daytime 1-hourly radiosondes and 10-minute ‘trailer’ radiosondes every 3 hours. These 12 intensive operational period (IOP) days were selected on the basis of prior-day qualitative forecasts of potential land-atmosphere coupling strength. The campaign captured 2 dry soil convection advantage days (June 29 and July 14) and 10 atmospherically controlled days. Other noteworthy IOP events include: 2 soil dry-down sequences (July 11-14-19 and August 21-25-26), a 2-day clear-sky case (August 15-16), and the passing of Tropical Storm Bill (June 18). To date, the ESLCS data set constitutes the highest-temporal-resolution sampling of the evolution of the daytime planetary boundary layer (PBL) using radiosondes at the ARM-SGP. This presentation will provide an overview of: (1) the ESLCS data set; (2) preliminary, unfunded analyses thereof; (3) ongoing research applications using the data set; and (4) further research opportunities, including plans for additional local coupling monitoring sites and data sets in support of a proposed Global Energy and Water cycle EXchanges (GEWEX) North American Hydroclimate Project. To date, the ESLCS data set has proven useful for validation and calibration of, for example, the Atmospheric Emitted Radiance Interferometer (AERI) and the Total Carbon Column Observing Network (TCCON). The data set’s 48 pairs of daytime 10-minute-lagged radiosondes has enabled warm-season uncertainty estimates of the raobs, which for 0-300 hPa above-ground-level (AGL) temperature, relative humidity, and specific humidity are: 0.24-0.29 K, 2.2- 3.4% and 0.36-0.41 g kg-1 , respectively. Inter-comparison of several PBL height estimates over the full daytime evolution captured by the campaign underscore the need for a single community best-practice. Under conditions of mid- and upper-level disturbances, a common local coupling metric was shown to be prone to false positives (for the influence of land). The importance of land-atmosphere coupling realism to weather and climate model skill necessitates observation-based model evaluation across a broader range of locations and biomes.