SOLAR ECLIPSE EFFECTS OBSERVED IN THE PLANETARY BOUNDARY LAYER OVER A DESERT

Abstract. An investigation of the Planetary Boundary Layer (PBL) height evolution over Greece, during the solar eclipse of 29 March 2006, is presented. Ground based observations were carried out using lidar detection and ranging devices and ground meteorological instruments, to estimate the height of the mixing layer (ML) before, during and after the solar eclipse in northern and southern parts of Greece exhibiting different sun obscuration. Data demonstrate that the solar eclipse has induced a decrease of the PBL height, indicating a suppression of turbulence activity similar to that during the sunset hours. The changes in PBL height were associated with a very shallow entrainment zone, indicating a significant weakening of the penetrative convection. Heat transfer was confined to a thinner layer above the ground. The thickness of the entrainment zone exhibited its minimum during the maximum of the eclipse, demonstrative of turbulence mechanisms suppression at that time. Model estimations of the PBL evolution were additionally conducted using the Comprehensive Air Quality Model with extensions (CAMx) coupled with the Weather Research and Forecasting model (WRF). Model-diagnosed PBL height decrease during the solar eclipse due to vertical transport decay, in agreement with the experimental findings; vertical profiles of atmospheric particles and gaseous species showed an important vertical mixing attenuation.

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Aerosol lidar observations and model calculations of the planetary boundary layer evolution over Greece, during the March 2006 total solar eclipse

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-13537-2007 ◽

2007 ◽

Vol 7 (5) ◽

pp. 13537-13560 ◽

Cited By ~ 7

Author(s):

V. Amiridis ◽

D. Melas ◽

D. S. Balis ◽

A. Papayannis ◽

D. Founda ◽

...

Keyword(s):

Boundary Layer ◽

Planetary Boundary Layer ◽

Solar Eclipse ◽

Wrf Model ◽

Air Quality Model ◽

Quality Model ◽

Gaseous Species ◽

Time Model ◽

Model Calculations ◽

Entrainment Zone

Abstract. An investigation of the Planetary Boundary Layer (PBL) height evolution over Greece, during the solar eclipse of 29 March 2006, is presented. Ground based observations were carried out using lidar detection and ranging devices (Lidars) and ground meteorological instruments, to estimate the height of the Mixing Layer (ML) before, during and after the solar eclipse in Northern and Southern parts of Greece exhibiting different sun obscuration. Data demonstrate that the solar eclipse has induced a decrease of the PBL height, indicating a suppression of turbulence activity similar to that during the sunset hours. The changes in PBL height were associated with a very shallow entrainment zone, indicating a significant weakening of the penetrative convection. Heat transfer was confined to a thinner layer above ground. The thickness of the entrainment zone exhibited its minimum during the maximum of the eclipse, demonstrative of turbulence mechanisms suppression at that time. Model estimations of the PBL evolution were additionally conducted using the Comprehensive Air Quality Model with extensions (CAMx) coupled with the Weather Research and Forecasting model (WRF). Model diagnosed PBL height decrease during the solar eclipse due to vertical transport decay, in agreement with the experimental findings; vertical profiles of atmospheric particles and gaseous species showed an important vertical mixing attenuation.

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Aerosol Lidar and in situ ozone observations of the planetary boundary layer over Bulgaria during the solar eclipse of 11 August 1999

International Journal of Remote Sensing ◽

10.1080/01431160500076939 ◽

2005 ◽

Vol 26 (16) ◽

pp. 3567-3584 ◽

Cited By ~ 21

Author(s):

N. Kolev ◽

B. Tatarov ◽

V. Grigorieva ◽

E. Donev ◽

P. Simeonov ◽

...

Keyword(s):

Boundary Layer ◽

Planetary Boundary Layer ◽

Solar Eclipse

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Lagrangian simulation of the passive tracer in the convective planetary boundary layer

Proceeding of THMT-15. Proceedings of the Eighth International Symposium On Turbulence Heat and Mass Transfer ◽

10.1615/ichmt.2015.thmt-15.1460 ◽

2015 ◽

Author(s):

Boris B. Ilyushin ◽

I.V Mitin ◽

Dmitrii Ph. Sikovsky

Keyword(s):

Boundary Layer ◽

Planetary Boundary Layer ◽

Passive Tracer ◽

Lagrangian Simulation ◽

Convective Planetary Boundary Layer

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Sensitivity of an Idealized Tropical Cyclone to the Configuration of the Global Forecast System–Eddy Diffusivity Mass Flux Planetary Boundary Layer Scheme

Atmosphere ◽

10.3390/atmos12020284 ◽

2021 ◽

Vol 12 (2) ◽

pp. 284

Author(s):

Evan A. Kalina ◽

Mrinal K. Biswas ◽

Jun A. Zhang ◽

Kathryn M. Newman

Keyword(s):

Boundary Layer ◽

Planetary Boundary Layer ◽

Weather Prediction ◽

Intensity Change ◽

Rapid Intensification ◽

Forecast System ◽

Stability Functions ◽

Non Local ◽

The Stability ◽

Heat And Moisture

The intensity and structure of simulated tropical cyclones (TCs) are known to be sensitive to the planetary boundary layer (PBL) parameterization in numerical weather prediction models. In this paper, we use an idealized version of the Hurricane Weather Research and Forecast system (HWRF) with constant sea-surface temperature (SST) to examine how the configuration of the PBL scheme used in the operational HWRF affects TC intensity change (including rapid intensification) and structure. The configuration changes explored in this study include disabling non-local vertical mixing, changing the coefficients in the stability functions for momentum and heat, and directly modifying the Prandtl number (Pr), which controls the ratio of momentum to heat and moisture exchange in the PBL. Relative to the control simulation, disabling non-local mixing produced a ~15% larger storm that intensified more gradually, while changing the coefficient values used in the stability functions had little effect. Varying Pr within the PBL had the greatest impact, with the largest Pr (~1.6 versus ~0.8) associated with more rapid intensification (~38 versus 29 m s−1 per day) but a 5–10 m s−1 weaker intensity after the initial period of strengthening. This seemingly paradoxical result is likely due to a decrease in the radius of maximum wind (~15 versus 20 km), but smaller enthalpy fluxes, in simulated storms with larger Pr. These results underscore the importance of measuring the vertical eddy diffusivities of momentum, heat, and moisture under high-wind, open-ocean conditions to reduce uncertainty in Pr in the TC PBL.

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