Estimation of cold pool areas and chilling hours through satellite-derived surface temperatures

Jiménez, María A.; Ruiz, Adela; Cuxart, Joan

doi:10.1016/j.agrformet.2015.03.017

Cited by 13 publications

(7 citation statements)

References 43 publications

(44 reference statements)

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“…Due to the topographical features of the Palma basin, the satellite‐derived averaged fields (LST and SST) are able to capture the main surface thermal patterns of the three basins whereas they are usually less accurate for areas with more complex terrain, such as in the mountain ranges (Jiménez et al ., 2015; 2020). Other satellites with higher spatial resolution could be used in this work, but their frequency of visit is too low to study the diurnal cycle of the SB.…”

Section: Description Of the Site And Datamentioning

confidence: 99%

Statistical characterization of the sea‐breeze physical mechanisms through in‐situ and satellite observations

Grau

Jiménez

Cuxart

2020

Intl Journal of Climatology

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The physical mechanisms that take place under sea-breeze (SB) conditions in the Palma basin (Mallorca island, western Mediterranean sea) are analysed through the inspection of data from automatic weather stations (AWS) during the period 2009-2017. Satellite-derived land-surface and sea-surface temperatures (LST and SST, respectively) are used to compute the surface temperature difference (LST-SST) in the Palma basin. It is found that during daytime hourly averages for each month of this difference are always positive and maximal during summer time. A method is proposed to select the SB events using data from AWS. SB conditions are mainly reported during the warm months of the year (from April to September). Results from the statistical analysis of the selected SB events show that the morning reversal strongly depends on the speed and direction of the large-scale winds. Besides, weak wind conditions are reported during the morning reversal and once the SB starts the cold advection from the sea counteracts the radiative heating and the 2-m temperature levels off. The maximum surface temperature difference under SB conditions is larger than 5 C and it is often reported several hours after the morning reversal. About 2 hr later the maximum wind speed is formed, strongly influenced by the amount of soil moisture.

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Section: Description Of the Site And Datamentioning

confidence: 99%

Statistical characterization of the sea‐breeze physical mechanisms through in‐situ and satellite observations

Grau

Jiménez

Cuxart

2020

Intl Journal of Climatology

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“…It may well happen that the pixel-averaged value or the local measurement point are in fact not representative of the actual conditions governing the surface atmosphere exchanges over each of the subpixel tiles. This would be important since it could provide inadequate values of surface temperature or sensible and latent energy fluxes for numerical models or agricultural applications [24]. Table 1.…”

Section: Introductionmentioning

confidence: 99%

Landsat and Local Land Surface Temperatures in a Heterogeneous Terrain Compared to MODIS Values

et al. 2016

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Land Surface Temperature (LST) as provided by remote sensing onboard satellites is a key parameter for a number of applications in Earth System studies, such as numerical modelling or regional estimation of surface energy and water fluxes. In the case of Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra or Aqua, pixels have resolutions near 1 km 2 , LST values being an average of the real subpixel variability of LST, which can be significant for heterogeneous terrain. Here, we use Landsat 7 LST decametre-scale fields to evaluate the temporal and spatial variability at the kilometre scale and compare the resulting average values to those provided by MODIS for the same observation time, for the very heterogeneous Campus of the University of the Balearic Islands (Mallorca, Western Mediterranean), with an area of about 1 km 2 , for a period between 2014 and 2016. Variations of LST between 10 and 20 K are often found at the sub-kilometre scale. In addition, MODIS values are compared to the ground truth for one point in the Campus, as obtained from a four-component net radiometer, and a bias of 3.2 K was found in addition to a Root Mean Square Error (RMSE) of 4.2 K. An indication of a more elaborated local measurement strategy in the Campus is given, using an array of radiometers distributed in the area.

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“…In this study, four or five available images per day from the moderate resolution imaging spectroradiometer (MODIS) (Salomonson et al, ), on board of the polar Terra and Aqua satellites, provide estimations of LST for the area of interest at an approximate nominal horizontal resolution of 1 × 1 km, for viewing angle observations close to nadir. LST is calculated using the generalized split‐window method, which performs corrections for atmospheric effects based on the differential absorption in the adjacent infrared bands and requires land surface emissivity as an input (Wan and Dozier, ; Jiménez et al, ).…”

Section: Methodsmentioning

confidence: 99%

“…CAPs in sinkholes and valleys have been extensively examined over the past few decades, but the mechanisms of their formation and evolution are not fully understood and still poorly modelled. The difference between the temperatures at the valley bottom and outside the valley can be several degrees (Martínez et al, ; Smith et al, ; Jiménez et al, ), reaching up to 20 °C difference in closed sinkholes (Iijima and Shinoda, ; Clements et al, ).…”

Section: Introductionmentioning

confidence: 99%

Cold‐air pool evolution in a wide Pyrenean valley

Conangla

Cuxart

Jiménez

et al. 2018

Intl Journal of Climatology

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This study on cold‐air pool formation in the wide Cerdanya Valley in the Pyrenees mountain range was conducted using available observational information from September 2010 to August 2014. Cold‐air pools occur during almost 60% of the nights, mainly during winter. Cold pools develop even under significant synoptic pressure gradients. Additionally, drainage currents transporting air down‐valley occur most of the nights. In particular one representative cold‐air pool event has been analysed in detail by a high‐resolution mesoscale simulation, combined with an analysis of data from both ground‐based stations and satellites. Radiative processes dominate the evolution of cold‐air pools, together with turbulence in the lowest layers, while drainage flows down from the high mountains mainly through the tributary valleys and from the valley sidewall slopes play a key role in bringing air to the pool. Cold pool formation begins approximately 1 hr after sunset, and it extends across most of the valley bottom, with a very strong thermal inversion close to the surface that has a depth of up to 100 m in the lowest parts of the valley. Wind veers down‐valley along the main axis 2–3 hr after sunset and the wind direction is approximately maintained until after sunrise.

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Estimation of cold pool areas and chilling hours through satellite-derived surface temperatures

Abstract: 8A methodology is proposed to identify the coldest areas of the island of Mallorca 9 through satellite-derived surface temperatures. Land-surface temperatures from the

Cited by 13 publications

References 43 publications

Statistical characterization of the sea‐breeze physical mechanisms through in‐situ and satellite observations

Statistical characterization of the sea‐breeze physical mechanisms through in‐situ and satellite observations

Landsat and Local Land Surface Temperatures in a Heterogeneous Terrain Compared to MODIS Values

Cold‐air pool evolution in a wide Pyrenean valley

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