H. Salmun

Estimating Planetary Boundary Layer Heights from NOAA Profiler Network Wind Profiler Data

AbstractAn algorithm was developed to estimate planetary boundary layer (PBL) heights from hourly archived wind profiler data from the NOAA Profiler Network (NPN) sites located throughout the central United States. Unlike previous studies, the present algorithm has been applied to a long record of publicly available wind profiler signal backscatter data. Under clear-sky conditions, summertime averaged hourly time series of PBL heights compare well with Richardson number–based estimates at the few NPN stations with hourly temperature measurements. Comparisons with estimates based on clear-sky reanalysis show that the wind profiler (WP) PBL heights are lower by approximately 250–500 m. The geographical distribution of daily maximum PBL heights corresponds well with the expected distribution based on patterns of surface temperature and soil moisture. Wind profiler PBL heights were also estimated under mostly cloudy-sky conditions, and are generally comparable to the Richardson number–based PBL heights and hi...

Scales of variability of surface vegetation: Calculation and implications for climate models

[1]xa0The presence in the vegetation landscape of many varied scales of organization implies a complex set of land/atmosphere interactions. Larger scales of variability at the surface induce boundary layer heterogeneity and may induce secondary boundary layer circulation patterns. The quantification of the scales of heterogeneity in the surface vegetation, therefore, is essential to the understanding and modeling of the land/atmosphere interactions. The present study analyzes the scales of heterogeneity in the surface vegetation by using a satellite-derived land class category map and a discrete analysis tool. Results show substantial variability in scales near 1000 km for most land class categories other than Deciduous Broadleaf Forest. Implications for GCM modeling approaches to the land/atmosphere interactions were drawn based on the results of the study. Results are consistent with the use of a ‘mosaic’ rather than a ‘mixture’ approach and with extending the ‘mosaic’ approach up through the boundary layer.