The Coastal Boundary Layer and Air Pollution - A High Temporal Resolution Analysis in the East Mediterranean Coast

Uzan, Leenes; Alpert, Pinhas

doi:10.2174/1874282301206010009

Cited by 16 publications

(16 citation statements)

References 27 publications

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“…after sunrise (Dayan et al, 1988;Feliks, 1994;Dayan and Rodnizki, 1999;Uzan et al, 2016;Yuval et al, 2020). The sea breeze front enters between 07:00 and 09:00 LST (Feliks, 1993;Alpert and Rabinovich-Hadar, 2003;Uzan and Alpert, 2012), depending on the time of sunrise and the different synoptic modes of the prevailing system -the Persian Trough (Alpert et al, 2004). Cool and humid marine air hinder the convective updrafts.…”

Section: The Summer Pbl Heightmentioning

confidence: 99%

“…Cool and humid marine air hinder the convective updrafts. Clouds dissolve, and the height of the shoreline boundary layer lowers by ∼ 250 m (Feliks, 1993(Feliks, , 1994Levi et al, 2011;Uzan and Alpert, 2012). Further inland, the convective thermals continue to inflate the boundary layer (Hashmonay et al, 1991;Feliks, 1993;Lieman and Alpert, 1993).…”

Section: The Summer Pbl Heightmentioning

confidence: 99%

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Ceilometers as planetary boundary layer height detectors and a corrective tool for COSMO and IFS models

et al. 2020

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Abstract. The significance of planetary boundary layer (PBL) height detection is apparent in various fields, especially in air pollution dispersion assessments. Numerical weather models produce a high spatial and temporal resolution of PBL heights; however, their performance requires validation. This necessity is addressed here by an array of eight ceilometers; a radiosonde; and two models – the Integrated Forecast System (IFS) global model and COnsortium for Small-scale MOdeling (COSMO) regional model. The ceilometers were analyzed with the wavelet covariance transform method, and the radiosonde and models with the parcel method and the bulk Richardson method. Good agreement for PBL height was found between the ceilometer and the adjacent Bet Dagan radiosonde (33 m a.s.l.) at 11:00 UTC launching time (N=91 d, ME =4 m, RMSE =143 m, R=0.83). The models' estimations were then compared to the ceilometers' results in an additional five diverse regions where only ceilometers operate. A correction tool was established based on the altitude (h) and distance from shoreline (d) of eight ceilometer sites in various climate regions, from the shoreline of Tel Aviv (h=5 m a.s.l., d=0.05 km) to eastern elevated Jerusalem (h=830 m a.s.l., d=53 km) and southern arid Hazerim (h=200 m a.s.l., d=44 km). The tool examined the COSMO PBL height approximations based on the parcel method. Results from a 14 August 2015 case study, between 09:00 and 14:00 UTC, showed the tool decreased the PBL height at the shoreline and in the inner strip of Israel by ∼100 m and increased the elevated sites of Jerusalem and Hazerim up to ∼400 m, and ∼600 m, respectively. Cross-validation revealed good results without Bet Dagan. However, without measurements from Jerusalem, the tool underestimated Jerusalem's PBL height by up to ∼600 m.

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Section: The Summer Pbl Heightmentioning

confidence: 99%

Section: The Summer Pbl Heightmentioning

confidence: 99%

Ceilometers as planetary boundary layer height detectors and a corrective tool for COSMO and IFS models

et al. 2020

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“…Although H b is expected to decrease significantly only after or close to sunset when turbulence decays (Stull 1988), the observations show a significant decrease throughout the afternoon. This may be due to the strong sea-breeze circulation for this period in this region, which weakens the vertical circulation as illustrated by Uzan and Alpert (2012) employing profiler data on the coast south of Haifa.…”

Section: General Featuresmentioning

confidence: 97%

Inner Structure of Atmospheric Inversion Layers over Haifa Bay in the Eastern Mediterranean

Haikin

Galanti

Reisin³

et al. 2015

Boundary-Layer Meteorol

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Capping inversions act as barriers to the vertical diffusion of pollutants, occasionally leading to significant low-level air pollution episodes in the lower troposphere. Here, we conducted two summer campaigns where global positioning system radiosondes were operated in Haifa Bay on the eastern Mediterranean coast, a region of steep terrain with significant pollution. The campaigns provided unique high resolution measurements related to capping inversions. It was found that the classical definition of a capping inversion was insufficient for an explicit identification of a layer; hence additional criteria are required for a complete spatial analysis of inversion evolution. Based on the vertical temperature derivative, an inner fine structure of inversion layers was explored, and was then used to track inversion layers spatially and to investigate their evolution. The exploration of the inner structure of inversion layers revealed five major patterns: symmetric peak, asymmetric peak, double peak, flat peak, and the zig-zag pattern. We found that the symmetric peak is related to the strongest inversions, double peak inversions tended to break apart into two layers, and the zig-zag pattern was related to the weakest inversions. Employing this classification is suggested for assistance in following the evolution of inversion layers.

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“…Comprehensive research of the Israeli summer PBL (Neumann, 1952, Neumann, 1977, Dayan 105 et al, 1988, Lieman, R. and Alpert, 1993, Hashmonay et al, 1991, Felix, 1993, Felix, 1994, Dayan and Rodnizki, 1999, Dayan et al, 2002, Alpert and Rabinovich-Hadar, 2003, Felix, 2004, Levi et al, 2011, Uzan and Alpert, 2012, Uzan et al 2016 is generally described in the following manner: After sunrise (~2-3 UTC) clouds initially formed over the Mediterranean Sea are advected eastward to the shoreline. As the ground warms up, the nocturnal surface 110 boundary layer (SBL) dissipates and buoyancy induced convective updrafts instigate the formation of the sea breeze circulation.…”

Section: Research Area 90mentioning

confidence: 99%

Ceilometers as planetary boundary layer detectors and a corrective tool for ECMWF and COSMO NWP models

Uzan

Egert

Khain

et al. 2019

Preprint

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<p><strong>Abstract.</strong> The growing importance of the planetary boundary layer (PBL) height detection is apparent in various fields, from air pollution analysis to weather prediction. In recent years micro-lidars such as ceilometers have been recognized as an efficient tool for such measurements. Here, the daytime summer PBL height is measured by eight ceilometers throughout Israel, along with with radiosonde profiles, the global IFS model, and the regional COSMO model. The analysis focused on three PBL height evaluation methods: the bulk Richardson method, the parcel method, and the wavelet covariance transform method. The best agreement between the PBL heights derived from a single radiosonde site on 33 summer days was found by the adjacent ceilometer (mean error = 12&#8201;m, RMSE = 97&#8201;m). Spatial analysis of the PBL heights derived from the models on 13 days in reference to five ceilometer measurement sites revealed COSMO evaluations by the bulk Richardson method (COSMOR) produced the best results for both flat (mean error = 19&#8201;m, RMSE = 203&#8201;m) and elevated terrain (mean error = &#8722;6&#8201;m, RMSE = 251&#8201;m). To improve COSMOR results, a regression tool was assimilated based on the PBL height difference between COSMOR and ceilometers. The regression is based on the altitude and distance from the shoreline for eight ceilometer sites.</p>

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The Coastal Boundary Layer and Air Pollution - A High Temporal Resolution Analysis in the East Mediterranean Coast

Cited by 16 publications

References 27 publications

Ceilometers as planetary boundary layer height detectors and a corrective tool for COSMO and IFS models

Ceilometers as planetary boundary layer height detectors and a corrective tool for COSMO and IFS models

Inner Structure of Atmospheric Inversion Layers over Haifa Bay in the Eastern Mediterranean

Ceilometers as planetary boundary layer detectors and a corrective tool for ECMWF and COSMO NWP models

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