Nocturnal boundary layer height prediction from surface routine meteorological data

Tombrou, M.; Founda, Dimitra; Boucouvala, D.

doi:10.1007/bf01030209

Cited by 5 publications

(3 citation statements)

References 11 publications

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“…These findings corroborate the stability regimes suggested by Malhi et al [62], where the first regime is related to clear sky conditions (case 1). This regime corresponds to a stable boundary layer configuration characterized by weak or intermittent turbulence, leading to layer stratification along the vertical profile [62][63][64][65][66][67] and to a boundary layer top that is well defined by an inflection point in potential temperature [66]. The second atmospheric regime of Malhi et al is related to partly cloudy or cloudy sky conditions (case 2), which is classified as a weakly stable boundary layer because turbulence tends to be continuous and deep [55,63,65].…”

Section: Resultsmentioning

confidence: 99%

Vertical Profiles of Ozone Concentration Collected by an Unmanned Aerial Vehicle and the Mixing of the Nighttime Boundary Layer over an Amazonian Urban Area

Guimaraes

Batista

et al. 2019

Atmosphere

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The nighttime boundary layer was studied in an urban area surrounded by tropical forest by use of a copter-type unmanned aerial vehicle (UAV) in central Amazonia during the wet season. Fifty-seven vertical profiles of ozone concentration, potential temperature, and specific humidity were collected from surface to 500 m above ground level (a.g.l.) at high vertical and temporal resolutions by use of embedded sensors on the UAV. Abrupt changes in ozone concentration with altitude served as a proxy of nighttime boundary layer (NBL) height for the case of a normal, undisturbed, stratified nighttime atmosphere, corresponding to 40% of the cases. The median height of the boundary layer was 300 m. A turbulent mixing NBL constituted 28% of the profiles, while the median height of the boundary layer was 290 m. The remaining 32% of profiles corresponded to complex atmospheres without clear boundary layer heights. The occurrence of the three different cases correlated well with relative cloud cover. The results show that the standard nighttime model widely implemented in chemical transport models holds just 40% of the time, suggesting new challenges in modeling of regional nighttime chemistry. The boundary layer heights were also somewhat higher than observed previously over forested and pasture areas in Amazonia, indicating the important effect of the urban heat island.

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Section: Resultsmentioning

confidence: 99%

Vertical Profiles of Ozone Concentration Collected by an Unmanned Aerial Vehicle and the Mixing of the Nighttime Boundary Layer over an Amazonian Urban Area

Guimaraes

Batista

et al. 2019

Atmosphere

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“…Esse comportamento pode estar relacionado com a maior ocorrência de turbulência intermitente neste período em função da turbulência mecânica . O qual, segundo Tombrou et al (1998), a turbulência na CLN é gerada especificamente por cisalhamento do vento, sendo este altamente intermitente. Verificou-se que a neste período a partir da 06 HL teve início a erosão da CLN, transição entre a fase noturna, com a fase diurna, no qual a estabilidade atmosférica presente começa a ser destruída e, ocorre o início da formação de uma camada instável próxima a superfície (Angevine, 2008), esta ocorreu de forma lenta apresentando uma taxa de crescimento em média de 50 m h -1 .…”

Section: Resultsunclassified

Avaliação do ciclo anual da Camada Limite Planetária na região Amazônica (Study of the annual cycle of the planetary boundary layer in the Amazon region)

Carneiro

Fisch

Borges

et al. 2018

RBGF

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“…We determined the top of the NBL as the lowest height where the vertical stratification of the atmosphere becomes isothermal (∂T/∂z = 0, Stull (1988); Tombrou et al (1998)). During the three events in this study, the NBL top at 1:00 CET of the events was at 730 m, 700 m, and 680 m a.g.l., respectively (Fig.…”

Section: Determination Of Atmospheric Layer Heightsmentioning

confidence: 99%

The role of dew and radiation fog inputs in the local water cycling of a temperate grassland in Central Europe

Li¹,

Aemisegger²,

Riedl³

et al. 2020

Preprint

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Abstract. In a warmer climate, non-rainfall water (hereafter NRW) formed from dew and fog potentially plays an increasingly important role in temperate grassland ecosystems under the scarcity of precipitation over prolonged periods. Dew and radiation fog occur in combination during clear and calm nights, and both use ambient water vapor as a source. Research on the combined mechanisms involved in NRW inputs to ecosystems are rare, and the condensation of soil-diffusing vapor, as one of the NRW input pathways for dew formation, has hardly been studied at all. The aim of this paper is thus to investigate the different NRW input pathways into a temperate Swiss grassland at Chamau during prolonged dry periods in summer 2018. We measured the isotopic compositions (δ18O, δ2H, and d = δ2H − 8 · δ18O) of both ambient water vapor and the NRW droplets on leaf surfaces combined with eddy covariance and meteorological measurements during one dew-only and two combined dew and radiation fog events. We employed a simple two end-member mixing model using δ18O and δ2H to split the dew input pathways from different sources. Our results showed a decrease of 0.8–5.5 mmol mol−1 in volumetric water vapor mixing ratio and a decrease of 4.8–16.7 ‰ in ambient water vapor δ2H due to dew formation and radiation fog droplet deposition. A nighttime maximum in ambient water vapor δ18O (−15.5 ‰ to −14.3 ‰) and a 3.4–3.7 ‰ decrease in ambient water vapor d were observed for dew formation in unsaturated conditions. In conditions of slight super-saturation, a stronger decrease of ambient water vapor δ18O (0.3–1.5 ‰) and a minimum of ambient water vapor d (−6.0 ‰ to −4.7 ‰) were observed. The combined foliage NRW and ambient water vapor δ18O and δ2H suggested two different input pathways: (1) condensation of ambient water vapor and (2) of soil-diffusing vapor. The latter contributed 9–42 % to the total foliage NRW. The dew and radiation fog potentially produced 0.06–0.39 mm night−1 NRW gain on foliage, which was comparable with 2.8 mm day−1 daytime evapotranspiration. The ambient water vapor d was correlated and anti-correlated with ambient temperature and ambient relative humidity respectively, suggesting an only minor influence of large-scale air advection and highlighted the dominant role of local moisture as a source for ambient water vapor. Our results thus highlight the importance of NRW inputs to temperate grasslands during prolonged dry periods and reveal the complexity of the local water cycle in such conditions including different pathways of water deposition.

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Nocturnal boundary layer height prediction from surface routine meteorological data

Cited by 5 publications

References 11 publications

Vertical Profiles of Ozone Concentration Collected by an Unmanned Aerial Vehicle and the Mixing of the Nighttime Boundary Layer over an Amazonian Urban Area

Vertical Profiles of Ozone Concentration Collected by an Unmanned Aerial Vehicle and the Mixing of the Nighttime Boundary Layer over an Amazonian Urban Area

Avaliação do ciclo anual da Camada Limite Planetária na região Amazônica (Study of the annual cycle of the planetary boundary layer in the Amazon region)

The role of dew and radiation fog inputs in the local water cycling of a temperate grassland in Central Europe

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