The Layered Structure of the Winter Atmospheric Boundary Layer in the Interior of Alaska

Abstract

The high-latitude winter atmospheric boundary layer of interior Alaska continually exhibits a complex layered structure as a result of extreme meteorological conditions. In this paper the occurrence of elevated inversions (EI), surface-based inversions (SBI), and stratified layers in the sub-Arctic from January 2000 to December 2009 is reported. This statistical analysis is based on radiosonde observation data from the Fairbanks National Weather Service station complemented by Winter Boundary Layer Experiment observations in the period 2010-11. This study found that SBIs occurred 64% of the time. An SBI occurred in combination with one, two, three, or four simultaneous EIs 84.86%, 48.49%, 21.23%, and 7.99% of the time, respectively, in 2326 total cases. The calculated mean SBI height was 377 m; EIs occurred at 1231, 2125, 2720, and 3125 m, respectively. This analysis was able to discriminate between locally controlled inversion layers and synopticdependent inversions and to identify their formation mechanisms. It was found that, in the presence of an SBI layer, the first EI layer formed 35.8% of the time under anticyclonic conditions at a mean height of 1249 m and 22% of the time in warm-air-advection situations at a mean height of 1049 m. The remaining 23.4% resulted from combined synoptic situations, and 18.8% were unclassified.

Evapotranspiration in Northern Agro-Ecosystems: Numerical Simulation and Experimental Comparison

“…In addition and based on local meteorological information, it was verified that the atmospheric boundary layer developed forced by surface and near surface flow conditions without presence of multilayered thermal inversions [35]. However, this condition is difficult to maintain when precipitation arises.…”

Investigation of inversion characteristics in atmospheric boundary layer: a case study of Tehran, Iran

“…SBI acts as a lid or barrier concerning near-surface and atmosphere constituent exchange (Zhang et al 2011). Depending upon the synoptic condition, the flow above the SBI may also develop thermal inversions called elevated inversion (EI) layers (Mayfield and Fochesatto 2013). To detect the inversion layers in the ABL, radiosonde method have been widely implemented by Zhang et al (2011), Mayfield and Fochesatto (2013) and Malingowski et al (2014).…”

“…Depending upon the synoptic condition, the flow above the SBI may also develop thermal inversions called elevated inversion (EI) layers (Mayfield and Fochesatto 2013). To detect the inversion layers in the ABL, radiosonde method have been widely implemented by Zhang et al (2011), Mayfield and Fochesatto (2013) and Malingowski et al (2014). This method depends on the application of temperature profiles that be extracted from upper air observation diagrams such as Skew-T.…”

Methodology for determining multilayered temperature inversions

“…Synoptic largescale meteorological processes condition the ABL state by driving relatively rapid horizontal air mass exchange for example under a cyclonic air mass advection (Fochesatto et al, 2002) or simply by imposing, on upper tropospheric levels, an adiabatic compression through the formation of a highpressure anticyclone (Byers and Starr 1941;Bowling et al, 1968;Curry, 1983;Cassano et al, 2011). These large-scale synoptic processes constrain the temperature of the air mass in tropospheric levels without initial connection to the local surface temperature forming vertically localized positive upward thermal gradients called elevated inversion (EI) layers (Csanady, 1974;Davies, 1992, 2008;Mayfield and Fochesatto, 2013).…”

“…Although the ABL timescale for surface response ranges from minutes to hours (Garrat and Brost, 1981;Stull, 1988), the ABL response to synoptic forcing at local scale initiated by the radiative and dynamic interaction in the presence of the EIs can vary from hours to several days depending on a number of factors related to topographic conditions, temperature and wind distribution, thermal stratification and synoptic air mass type (e.g., moist cyclone advection or dry anticyclone situations, Mayfield and Fochesatto, 2013).…”