Modeling the exceptional south Foehn event (Garmij) over the Alborz Mountains during the extreme forest fire of December 2005

Mofidi, Abbas; Soltanzadeh, Iman; Yousefi, Yadollah; Zarrin, Azar; Soltani, Mohsen; Samakosh, Jafar Masoompour; Ghasem, Azizi; Miller, Samuel T. K.

doi:10.1007/s11069-014-1440-9

Cited by 15 publications

(5 citation statements)

References 55 publications

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“…Lower values for LFMC, RWC and DFMC were found in the central region that was urbanized with relatively higher temperatures driving possibly dry live fuels, and northern slopes of the study area that are dominated by the south dry warm Foehn wind [58]. Dry warm Foehn wind is created by wind travelling from southern to northern slopes over the Alborz mountain range, which dries fuels and makes ideal conditions for rapid spread of fires in the forested area.…”

Section: Mapping Leaf Moisture and Dry Matter Content (Mci) Using Etmmentioning

confidence: 84%

Estimating and Up-Scaling Fuel Moisture and Leaf Dry Matter Content of a Temperate Humid Forest Using Multi Resolution Remote Sensing Data

2016

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Vegetation moisture and dry matter content are important indicators in predicting the behavior of fire and it is widely used in fire spread models. In this study, leaf fuel moisture content such as Live Fuel Moisture Content (LFMC), Leaf Relative Water Content (RWC), Dead Fuel Moisture Content (DFMC), and Leaf Dry Matter Content (LDMC) (hereinafter known as moisture content indices (MCI)) were calculated in the field for different forest species at 32 sites in a temperate humid forest (Zaringol forest) located in northeastern Iran. These data and several relevant vegetation-biophysical indices and atmospheric variables calculated using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data with moderate spatial resolution (30 m) were used to estimate MCI of the Zaringol forest using Artificial Neural Network (ANN) and Multiple Linear Regression (MLR) methods. The prediction of MCI using ANN showed that ETM+ predicted MCI slightly better (Mean Absolute Percentage Error (MAPE) of 6%-12%)) than MLR (MAPE between 8% and 17%). Once satisfactory results in estimating MCI were obtained by using ANN from ETM+ data, these data were then upscaled to estimate MCI using MODIS data for daily monitoring of leaf water and leaf dry matter content at 500 m spatial resolution. For MODIS derived LFMC, LDMC, RWC, and DLMC, the ANN produced a MAPE between 11% and 29% for the indices compared to MLR which produced an MAPE of 14%-33%. In conclusion, we suggest that upscaling is necessary for solving the scale discrepancy problems between the indicators and low spatial resolution MODIS data. The scaling up of MCI could be used for pre-fire alert system and thereby can detect fire prone areas in near real time for fire-fighting operations.

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Section: Mapping Leaf Moisture and Dry Matter Content (Mci) Using Etmmentioning

confidence: 84%

Estimating and Up-Scaling Fuel Moisture and Leaf Dry Matter Content of a Temperate Humid Forest Using Multi Resolution Remote Sensing Data

2016

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“…Many numerical modeling studies have been performed to explain the generation/development of observed downslope windstorms [10][11][12][13][14][15]. Decker and Robinson [10] showed that the downslope windstorm in New Jersey is caused by hydraulic jump or trapped lee waves, using a regime diagram suggested by [16], and partial reflection is not enough to explain the observed wind speed.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study of Windstorms in the Lee of the Taebaek Mountains, South Korea: Characteristics and Generation Mechanisms

Lee¹,

Seo

Baik³

et al. 2020

Atmosphere

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The Yeongdong region, located east of the Taebaek Mountains, South Korea, often experiences severe windstorms in spring, causing a lot of damages, especially when forest fires spread out rapidly by strong winds. Here, the characteristics and generation mechanisms of the windstorms in the Yeongdong region on 8 April 2012 are examined through a high-resolution Weather Research and Forecasting (WRF) model simulation. In the Yangyang area, the steep descent of the isentropes on the lee slope of the mountain and their recovery farther leeward are seen. Inversion layers and incoming flow in hydraulic jump regime suggest that the hydraulic jump is responsible for the downslope windstorm. In the Jangjeon area, the plume-shaped wind pattern extending seaward from the gap exit is seen when the sea-level pressure difference between the gap inside and the gap exit, being responsible for the gap winds, is large. In the Uljin area, downslope windstorms pass over the region with weak wind, low Richardson number, and deep planetary boundary layer (PBL), making banded pattern in the wind and PBL height fields. This study demonstrates that the characteristics of the windstorms in the lee of the Taebaek Mountains and their generation mechanisms differ depending on local topographic features.

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“…The mountain wave activity is extremely strong compared to other föhn studies (e.g., [24,66,67]), visible in the high vertical wind velocities (Figure 8b) causing vertically oriented isentropes (Figure 8c). These are a feature of a local static instability leading to nonlinear flows associated with intense turbulence and wave-breaking [66]. The near-surface easterly flow (Figure 8a) implies the formation of mountain-wave rotors, a phenomenon that is often observed together with the existence of a hydraulic jump [68].…”

Section: Classification Into Föhn Typesmentioning

confidence: 63%

“…Studies have shown that severe local downslope winds are often associated with the existence of a hydraulic jump [28,65]. The mountain wave activity is extremely strong compared to other föhn studies (e.g., [24,66,67]), visible in the high vertical wind velocities (Figure 8b) causing vertically oriented isentropes (Figure 8c). These are a feature of a local static instability leading to nonlinear flows associated with intense turbulence and wave-breaking [66].…”

Section: Classification Into Föhn Typesmentioning

confidence: 88%

Flow Regimes and Föhn Types Characterize the Local Climate of Southern Patagonia

et al. 2020

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The local climate in Southern Patagonia is strongly influenced by the interaction between the topography and persistent westerlies, which can generate föhn events, dry and warm downslope winds. The upstream flow regime influences different föhn types which dictate the lee-side atmospheric response regarding the strength, spatial extent and phenomenology. We use a combination of observations from four automatic weather stations (AWSs) and high-resolution numerical modeling with the Weather Research and Forecasting (WRF) model for a region in Southern Patagonia (48° S–52° S, 72° W–76.5° W) including the Southern Patagonian Icefield (SPI). The application of a föhn identification algorithm to a 10-month study period (June 2018–March 2019) reveals 81 föhn events in total. A simulation of three events of differing flow regimes (supercritical, subcritical, transition) suggests that a supercritical flow regime leads to a linear föhn event with a large spatial extent but moderate intensity. In contrast, a spatially limited but locally strong föhn response is induced by a subcritical regime with upstream blocking and by a transition regime with a hydraulic jump present. Our results imply that the hydraulic jump-type föhn event (transition case) is the most critical for glacier mass balances since it shows the strongest warming, drying, wind velocities and solar radiation over the SPI. The consideration of flow regimes over the last 40 years shows that subcritical flow occurs most frequently (78%), however transitional flow occurs 14% of the time, implying the potential impact on Patagonian glaciers.

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Modeling the exceptional south Foehn event (Garmij) over the Alborz Mountains during the extreme forest fire of December 2005

Cited by 15 publications

References 55 publications

Estimating and Up-Scaling Fuel Moisture and Leaf Dry Matter Content of a Temperate Humid Forest Using Multi Resolution Remote Sensing Data

Estimating and Up-Scaling Fuel Moisture and Leaf Dry Matter Content of a Temperate Humid Forest Using Multi Resolution Remote Sensing Data

A Numerical Study of Windstorms in the Lee of the Taebaek Mountains, South Korea: Characteristics and Generation Mechanisms

Flow Regimes and Föhn Types Characterize the Local Climate of Southern Patagonia

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