Estimating climatological planetary boundary layer heights from radiosonde observations: Comparison of methods and uncertainty analysis
نویسندگان
چکیده
[1] Planetary boundary layer (PBL) processes control energy, water, and pollutant exchanges between the surface and free atmosphere. However, there is no observation‐ based global PBL climatology for evaluation of climate, weather, and air quality models or for characterizing PBL variability on large space and time scales. As groundwork for such a climatology, we compute PBL height by seven methods, using temperature, potential temperature, virtual potential temperature, relative humidity, specific humidity, and refractivity profiles from a 10 year, 505‐station radiosonde data set. Six methods are directly compared; they generally yield PBL height estimates that differ by several hundred meters. Relative humidity and potential temperature gradient methods consistently give higher PBL heights, whereas the parcel (or mixing height) method yields significantly lower heights that show larger and more consistent diurnal and seasonal variations (with lower nighttime and wintertime PBLs). Seasonal and diurnal patterns are sometimes associated with local climatological phenomena, such as nighttime radiation inversions, the trade inversion, and tropical convection and associated cloudiness. Surface‐based temperature inversions are a distinct type of PBL that is more common at night and in the morning than during midday and afternoon, in polar regions than in the tropics, and in winter than other seasons. PBL height estimates are sensitive to the vertical resolution of radiosonde data; standard sounding data yield higher PBL heights than high‐resolution data. Several sources of both parametric and structural uncertainty in climatological PBL height values are estimated statistically; each can introduce uncertainties of a few 100 m.
منابع مشابه
Climatological Characteristics of Arctic and Antarctic Surface-Based Inversions*
Surface-based inversions (SBIs) are frequent features of the Arctic and Antarctic atmospheric boundary layer. They influence vertical mixing of energy, moisture and pollutants, cloud formation, and surface ozone destruction. Their climatic variability is related to that of sea ice and planetary albedo, important factors in climate feedback mechanisms. However, climatological polar SBI propertie...
متن کاملThree years of routine Raman lidar measurements of tropospheric aerosols: Planetary boundary layer heights, extinction and backscatter coefficients
We have performed a three-year series of routine lidar measurements on a climatological base. To obtain an unbiased data set, the measurements were taken at preselected times. The measurements were performed between 1 December 1997, and 30 November 2000, at Kühlungsborn, Germany (54◦07′N, 11◦46′ E). Using a 5 Rayleigh/Mie/Raman lidar system, we measured the aerosol backscatter coefficients at t...
متن کاملPerformance Evaluation of the Boundary-Layer Height from Lidar and the Weather Research and Forecasting Model at an Urban Coastal Site in the North-East Iberian Peninsula
We evaluate planetary boundary-layer (PBL) parametrizations in the Weather Research and Forecasting (WRF) numerical model, with three connected objectives: first, for a 16-year period, we use a cluster analysis algorithm of three-day back-trajectories to determine general synoptic flow patterns over Barcelona, Spain arriving at heights of 0.5, 1.5, and 3 km; to represent the lower PBL, upper PB...
متن کاملDiurnal cycle of upper-air temperature estimated from radiosondes
[1] This study estimates the amplitude and phase of the climatological diurnal cycle of temperature, from the surface to 10 hPa. The analysis is based on four-times-daily radiosonde data from 53 stations in four regions in the Northern Hemisphere, equatorial soundings from the Tropical Ocean Global Atmosphere/Coupled Ocean Atmosphere Response Experiment, and more recent eight-times-daily radios...
متن کاملContinuous monitoring of the boundary-layer top with lidar
Continuous lidar observations of the top height of the boundary layer (BL top) have been performed at Leipzig (51.3 • N, 12.4 • E), Germany, since August 2005. The results of measurements taken with a compact, automated Raman lidar over a one-year 5 determination of the BL top are discussed. The most promising technique, the wavelet covariance algorithm, is improved by implementing some modific...
متن کامل