Intercomparison of Mixing Layer Heights from the National Weather Service Ceilometer Test Sites and Collocated Radiosondes

Abstract

A network of automated weather stations (AWS) with ceilometers can be used to detect sky conditions, aerosol dispersion, and mixing layer heights, in addition to the routine surface meteorological parameters (temperature, pressure, humidity, etc.). Currently, a dense network of AWSs that observe all of these parameters does not exist in the United States even though networks of them with ceilometers exist. These networks normally use ceilometers for determining only sky conditions. Updating AWS networks to obtain those nonstandard observations with ceilometers, especially mixing layer height, across the United States would provide valuable information for validating and improving weather/climate forecast models. In this respect, an aerosol-based mixing layer height detection method, called the combined-hybrid method, is developed and evaluated for its uncertainty characteristics for application in the United States. Four years of ceilometer data from the National Weather Service Ceilometer Proof of Concept Project taken in temperate, maritime polar, and hot/arid climate regimes are utilized in this evaluation. Overall, the method proved to be a strong candidate for estimating mixing layer heights with ceilometer data, with averaged uncertainties of 237 6 398 m in all tested climate regimes and 69 6 250 m when excluding the hot/arid climate regime.

Challenges and Opportunities in Lidar Remote Sensing

“…Global ceilometer (a simple elastic lidar) network is the most successful lidar network to support operation so far. Current efforts in using ceilometer vertical profiles to characterize the Planetary Boundary Layer (PBL) structure will further empower the ceilometer network (Hicks et al, 2019). Lidar technologies for temperature, water vapor, and wind measurements, which are regarded as a high priority to fill observation gaps (especially within PBL) to improve weather and air quality prediction, are mature for operational lidar networks in the near future (Goldsmith et al, 1998;Nehrir et al, 2011;Reichardt et al, 2012;Weckwerth et al, 2016;Wu et al, 2016).…”

Assessment of Planetary Boundary Layer Parameterizations and Urban Heat Island Comparison: Impacts and Implications for Tracer Transport

“…In addition, a height constraint based on the lifting condensation level (LCL) is applied for both techniques. Details of the methods can be found in Hicks et al (2015Hicks et al ( , 2019.…”

“…In Hicks et al (2015Hicks et al ( , 2019 the consistency rate (Co) parameter was defined as the percentage of the ceilometer PBLH observations that measured within ± m when compared to radiosondes. The consistency rate reported in these previous works for the PBLH retrieval methods employed was 65 % for unstable conditions and 74 % for stable conditions.…”

Capabilities of an Automatic Lidar Ceilometer to Retrieve Aerosol Characteristics within the Planetary Boundary Layer

“…Ceilometers have been widely used to observe cloud base height and mixing layer height (MLH) and are deployed as networks due to unattended operation and easy maintenance [1,2]. Many efforts have been made to optimize or evaluate the algorithm for the MLH estimation [3][4][5][6][7][8][9].…”