scholarly journals Spatial Analysis of the Factors Contributing to the Relationship between the Transient, Meridional Eddy Sensible, and Latent Heat Flux in the Southern Hemisphere

2010 ◽  
Vol 32 (2) ◽  
pp. 140-153
Author(s):  
Marilyn Raphael ◽  
Steve Cherry
Keyword(s):  
Heat Flux ◽  
Spatial Analysis ◽  
Southern Hemisphere ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
The Relationship

scholarly journals Are Soil Moisture and Latent Heat Overcoupled in Land Models?

Eos ◽  
2019 ◽  
Vol 100 ◽  
Author(s):  
Aaron Sidder
Keyword(s):  
Remote Sensing ◽  
Heat Flux ◽  
Soil Moisture ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Coupling Strength ◽  
Statistical Approach ◽  
Flux Coupling ◽  
The Relationship

A novel statistical approach demonstrates how to reduce bias in remote sensing estimates of soil moisture and latent heat flux coupling strength and clarifies the relationship between the variables.

scholarly journals A preliminary evaluation of surface latent heat flux as an earthquake precursor

2013 ◽  
Vol 13 (10) ◽  
pp. 2639-2647 ◽  
Author(s):  
W. Zhang ◽  
J. Zhao ◽  
W. Wang ◽  
H. Ren ◽  
L. Chen ◽  
...  
Keyword(s):  
Heat Flux ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Regional Analysis ◽  
Earthquake Precursor ◽  
Preliminary Evaluation ◽  
Surface Latent Heat Flux ◽  
Popular Subject ◽  
The Relationship

Abstract. The relationship between variations in surface latent heat flux (SLHF) and marine earthquakes has been a popular subject of recent seismological studies. So far, there are two key problems: how to identify the abnormal SLHF variations from complicated background signals, and how to ensure that the anomaly results from an earthquake. In this paper, we proposed four adjustable parameters for identification, classified the relationship and analyzed SLHF changes several months before six marine earthquakes by employing daily SLHF data. Additionally, we also quantitatively evaluate the long-term relationship between earthquakes and SLHF anomalies for the six study areas over a 20 yr period preceding each earthquake. The results suggest the following: (1) before the South Sandwich Islands, Papua, Samoa and Haiti earthquakes, the SLHF variations above their individual background levels have relatively low amplitudes and are difficult to be considered as precursory anomalies; (2) after removing the clustering effect, most of the anomalies prior to these six earthquakes are not temporally related to any earthquake in each study area in time sequence; (3) for each case, apart from Haiti, more than half of the studied earthquakes, which were moderate and even devastating earthquakes (larger than Mw = 5.3), had no precursory variations in SLHF; and (4) the correlation between SLHF and seismic activity depends largely on data accuracy and parameter settings. Before any application of SLHF data on earthquake prediction, we suggest that anomaly-identifying standards should be established based on long-term regional analysis to eliminate subjectivity. Furthermore, other factors that may result in SLHF variations should also be carefully considered.

scholarly journals Impacts of wildfire aerosols on global energy budget and climate: The role of climate feedbacks

2020 ◽  
Author(s):  
Yiquan Jiang ◽  
Xiu-Qun Yang ◽  
Xiaohong Liu
Keyword(s):  
Heat Flux ◽  
Southern Hemisphere ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Global Climate ◽  
The Arctic ◽  
Global Ocean ◽  
Climate Feedbacks ◽  
Surface Latent Heat Flux

<p>Aerosols emitted from wildfires could significantly affect global climate through perturbing global radiation balance. In this study, Community Earth System Model with prescribed daily fire aerosol emissions is used to investigate fire aerosols’ impacts on global climate with emphasizing the role of climate feedbacks. The total global fire aerosol radiative effect (RE) is estimated to be -0.78±0.29 W m<sup>-2</sup>, which is mostly from shortwave RE due to aerosol-cloud interactions (REaci, -0.70±0.20 W m<sup>-2</sup>). The associated global-annual mean surface air temperature (SAT) change (∆T) is -0.64±0.16K with the largest reduction in the Arctic regions where the shortwave REaci is strong. Associated with the cooling, the Arctic sea ice is increased, which acts to re-amplify the Arctic cooling through a positive ice-albedo feedback. The fast response (irrelevant to ∆T) tends to decrease surface latent heat flux into atmosphere in the tropics to balance strong atmospheric fire black carbon absorption, which reduces the precipitation in the tropical land regions (southern Africa and South America). The climate feedback processes (associated with ∆T) lead to a significant surface latent heat flux reduction over global ocean areas, which could explain most (~80%) of the global precipitation reduction. The precipitation significantly decreases in deep tropical regions (5°N), but increases in Southern Hemisphere tropical ocean, which is associated with the southward shift of the Inter-Tropical Convergence Zone and the weakening of Southern Hemisphere Hadley cell. Such changes could partly compensate the interhemispheric temperature asymmetry induced by boreal-forest fire aerosol indirect effect, through intensifying the cross-equator atmospheric heat transport.</p>

scholarly journals A preliminary evaluation of surface latent heat flux as an earthquake precursor

2013 ◽  
Vol 1 (3) ◽  
pp. 2667-2693 ◽  
Author(s):  
W. Zhang ◽  
J. Zhao ◽  
W. Wang ◽  
H. Ren ◽  
L. Chen ◽  
...  
Keyword(s):  
Heat Flux ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Regional Analysis ◽  
Earthquake Precursor ◽  
Preliminary Evaluation ◽  
Surface Latent Heat Flux ◽  
Popular Subject ◽  
The Relationship

Abstract. The relationship between variations in surface latent heat flux (SLHF) and marine earthquakes has been a popular subject of recent seismological studies. So far, there are two key problems: how to identify the abnormal SLHF variations from complicated background signals, and how to ensure that the anomaly results from earthquake. In this paper, we proposed four adjustable parameters for identification, classified the relationship and analyze SLHF changes several months before six marine earthquakes by employing daily SLHF data. Besides, we also quantitatively evaluate the long-term relationship between earthquakes and SLHF anomalies for the six study areas over a 20 yr period preceding each earthquake. The results suggest: (1) before the South Sandwich Islands, Papua, Samoa and Haiti earthquakes, the SLHF variations above their individual background levels have relatively low amplitudes and are difficult to be considered as precursory anomalies; (2) after removing the clustering effect, most of the anomalies prior to these six earthquakes are not temporally related to any earthquake in each study area in time sequence; (3) for each case, apart from Haiti, more than half of studied earthquakes which were moderate even devastating earthquakes (larger than Mw = 5.3) had no precursory variations in SLHF; and (4) the correlation between SLHF and seismic activity depends largely on data accuracy and parameter settings. Before any application of SLHF data on earthquake prediction, we suggest that anomaly-identifying standards should be established based on long-term regional analysis to eliminate subjectivity. Furthermore, other factors which may result in SLHF variations also should be carefully considered.

scholarly journals Impacts of Wildfire Aerosols on Global Energy Budget and Climate: The Role of Climate Feedbacks

2020 ◽  
Vol 33 (8) ◽  
pp. 3351-3366 ◽  
Author(s):  
Yiquan Jiang ◽  
Xiu-Qun Yang ◽  
Xiaohong Liu ◽  
Yun Qian ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Heat Flux ◽  
Southern Hemisphere ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Global Climate ◽  
The Arctic ◽  
Global Ocean ◽  
Climate Feedbacks ◽  
Surface Latent Heat Flux

AbstractAerosols emitted from wildfires could significantly affect global climate through perturbing global radiation balance. In this study, the Community Earth System Model with prescribed daily fire aerosol emissions is used to investigate fire aerosols’ impacts on global climate with emphasis on the role of climate feedbacks. The total global fire aerosol radiative effect (RE) is estimated to be −0.78 ± 0.29 W m−2, which is mostly from shortwave RE due to aerosol–cloud interactions (REaci; −0.70 ± 0.20 W m−2). The associated global annual-mean surface air temperature (SAT) change ∆T is −0.64 ± 0.16 K with the largest reduction in the Arctic regions where the shortwave REaci is strong. Associated with the cooling, the Arctic sea ice is increased, which acts to reamplify the Arctic cooling through a positive ice-albedo feedback. The fast response (irrelevant to ∆T) tends to decrease surface latent heat flux into atmosphere in the tropics to balance strong atmospheric fire black carbon absorption, which reduces the precipitation in the tropical land regions (southern Africa and South America). The climate feedback processes (associated with ∆T) lead to a significant surface latent heat flux reduction over global ocean areas, which could explain most (~80%) of the global precipitation reduction. The precipitation significantly decreases in deep tropical regions (5°N) but increases in the Southern Hemisphere tropical ocean, which is associated with the southward shift of the intertropical convergence zone and the weakening of Southern Hemisphere Hadley cell. Such changes could partly compensate the interhemispheric temperature asymmetry induced by boreal forest fire aerosol indirect effects, through intensifying the cross-equator atmospheric heat transport.

Characterizing the relationship between temperature and soil moisture extremes and their role in the exacerbation of heatwaves over the contiguous United States

2020 ◽  
pp. 1-39
Author(s):  
David O. Benson ◽  
Paul A. Dirmeyer
Keyword(s):  
United States ◽  
Heat Flux ◽  
Soil Moisture ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Sensible Heat Flux ◽  
Reanalysis Data ◽  
Sensible Heat ◽  
The Us ◽  
The Relationship

AbstractIncreased heatwave frequency across the United States has led to the need for improved predictability of heatwave events. A detailed understanding of land-atmosphere interactions and the relationship between soil moisture and temperature extremes could provide useful information for prediction. This study identifies, for many locations, a threshold of soil moisture below which there is an increase in the sensitivity of atmospheric temperature to declining soil moisture. This shift to a hypersensitive regime causes the atmosphere to be more susceptible to atmospherically driven heatwave conditions. The soil moisture breakpoint where the regime shift occurs is estimated using segmented regression applied to observations and reanalysis data. It is shown that as the soil gets drier, there is a concomitant change in the rate of decrease in latent heat flux and increase in sensible heat flux leading to a strong positive feedback of increased air temperature near the surface, which further dries out the soil. Central, southwestern and southeastern parts of the US seem to have regions of clear regime shifts, while the eastern part of the US generally does not get dry enough to reveal significant breakpoints. Sensible heat flux is seen to be a primary driver of this increased temperature sensitivity aided by the drop in latent heat flux. An investigation of flux tower sites verifies the breakpoint-flux relationships found in reanalysis data. Accurate estimation of these breakpoints can contribute to improved heatwave prediction.

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