scholarly journals Latitudinal variation in herbivory: hemispheric asymmetries and the role of climatic drivers

2016 ◽  
Vol 104 (4) ◽  
pp. 1089-1095 ◽  
Author(s):  
Shuang Zhang ◽  
Yuxin Zhang ◽  
Keming Ma
Keyword(s):  
Latitudinal Variation ◽  
Hemispheric Asymmetries ◽  
Climatic Drivers

Hemispheric Asymmetries for Connecting and Predictive Inferences: The Role of Causal Constraint and Textual Familiarity

2000 ◽  
Author(s):  
Brian A. Sundermeier ◽  
Sandra Virtue ◽  
Paul van den Broek ◽  
Chad J. Marsolek ◽  
Tracy Linderholm
Keyword(s):  
Hemispheric Asymmetries ◽  
Causal Constraint ◽  
Predictive Inferences

scholarly journals Climate, tectonics or morphology: what signals can we see in drainage basin sediment yields?

2013 ◽  
Vol 1 (1) ◽  
pp. 13-27 ◽  
Author(s):  
T. J. Coulthard ◽  
M. J. Van de Wiel
Keyword(s):  
Sediment Yield ◽  
Drainage Basin ◽  
Sediment Yields ◽  
Internal Storage ◽  
Storage Effects ◽  
Climatic Drivers ◽  
Basin Morphology ◽  
The Impact ◽  
Small Basin

Abstract. Sediment yields from river basins are typically considered to be controlled by tectonic and climatic drivers. However, climate and tectonics can operate simultaneously and the impact of autogenic processes scrambling or shredding these inputs can make it hard to unpick the role of these drivers from the sedimentary record. Thus an understanding of the relative dominance of climate, tectonics or other processes in the output of sediment from a basin is vital. Here, we use a numerical landscape evolution model (CAESAR) to specifically examine the relative impact of climate change, tectonic uplift (instantaneous and gradual) and basin morphology on sediment yield. Unexpectedly, this shows how the sediment signal from significant rates of uplift (10 m instant or 25 mm a−1) may be lost due to internal storage effects within even a small basin. However, the signal from modest increases in rainfall magnitude (10–20%) can be seen in increases in sediment yield. In addition, in larger basins, tectonic inputs can be significantly diluted by regular delivery from non-uplifted parts of the basin.

Hotspots of extreme compound drought and heatwaves: Role of feedback and climate oscillations

2021 ◽  
Author(s):  
Waqar Ul Hassan ◽  
Munir Ahmad Nayak
Keyword(s):  
Large Scale ◽  
Southern Oscillation ◽  
Standardized Precipitation Index ◽  
Limited Attention ◽  
Weather Events ◽  
Excess Heat Factor ◽  
Climatic Drivers ◽  
Compound Events ◽  
Positive And Negative Feedbacks

<p>Compound weather events arise from combination of multiple climatic drivers or hazards and often result in disastrous socio-economic impacts. Compound drought and heatwave (CDHE) events have received considerable attention in recent years, but limited attention is given towards the understanding of feedback relationships between droughts and heatwaves at global hotspots of the compound events. Here, we identify the potential hotspots of extreme compound drought and heatwaves (ECDH) over the globe using standardized precipitation index (SPI) and Excess heat factor (EHF) as metrics for droughts and heatwaves, respectively. Besides the well know positive feedback between droughts and heatwaves, i.e., heatwaves amplify droughts and vice-versa, we hypothesize and test the possibility of negative feedback at distinct hotspots where heatwaves tend to abate droughts. Multiple hotspots were identified with positive and negative feedbacks among drought and heatwave intensities, supporting our hypothesis. We also analyzed the role of different local and large-scale global drivers (such as El-Niño Southern Oscillation) on the feedbacks at the hotspots. Our analysis has implications in predicting extreme compound droughts and heatwaves and provides new insights that will foster further research in this direction.</p>

scholarly journals COVID19 is a seasonal climate-driven disease across both hemispheres

2020 ◽  
Author(s):  
Alejandro Fontal ◽  
Menno J. Bouma ◽  
Adrià San José ◽  
Mercedes Pascual ◽  
Xavier Rodó
Keyword(s):  
Population Dynamics ◽  
Low Temperature ◽  
Spatial Scales ◽  
Absolute Humidity ◽  
Control Measures ◽  
Negative Effects ◽  
Climatic Drivers ◽  
Effects Of Temperature ◽  
Second Wave

The role of climate in the population dynamics of COVID-19 remains poorly understood, and a true seasonal signature has remained elusive. Data from both hemispheres and the second wave provide opportunities to further examine climatic drivers. With a statistical method designed to detect transitory associations, we show consistent negative effects of temperature and absolute humidity at large spatial scales. At finer spatial resolutions we substantiate these connections during the seasonal rise and fall of COVID-19. Strong disease responses are identified between 12-18°C for Temperature and 4-12 g/m3 for Absolute Humidity. These results classify COVID-19 as a seasonal low-temperature infection, and point to the airborne pathway as an important contribution to transmission for SARS-CoV-2, with implications for control measures we discuss.

scholarly journals Latitudinal variation in herbivory: influences of climatic drivers, herbivore identity and natural enemies

Oikos ◽  
2015 ◽  
Vol 124 (11) ◽  
pp. 1444-1452 ◽  
Author(s):  
Xoaquín Moreira ◽  
Luis Abdala-Roberts ◽  
Víctor Parra-Tabla ◽  
Kailen A. Mooney
Keyword(s):  
Natural Enemies ◽  
Latitudinal Variation ◽  
Climatic Drivers

Hydro-climatic drivers of mid-winter break-up of river ice in western Canada and Alaska

2016 ◽  
Vol 48 (4) ◽  
pp. 945-956 ◽  
Author(s):  
B. W. Newton ◽  
T. D. Prowse ◽  
L. P. de Rham
Keyword(s):  
Ice Cover ◽  
Climatic Conditions ◽  
River Ice ◽  
Western Canada ◽  
The North ◽  
Temperature And Precipitation ◽  
Tropospheric Circulation ◽  
Climatic Drivers ◽  
Break Up

The mid-winter break-up of a competent river ice cover can cause ice jamming and flooding, which can have profound impacts on the structure and strength of the ice cover. This research identifies 52 mid-winter break-up events in western Canada (1950–2008) and Alaska (1950–2014) and evaluates the hydro-climatic drivers including temperature and precipitation. The identified mid-winter break-up events are primarily located in the temperate zone, defined as the region between 400 and 1,000 winter (December–February) freezing degree-days. Further delineation by terrestrial biome revealed considerable variability in hydro-climatic triggers, particularly the role of freeze-thaw days (Tmax > 0 °C and Tmin < 0 °C) in Tundra and Boreal Forest/Taiga biomes and short-term (3-day) warming events in Temperate Coniferous Forests and Temperate Grasslands, Savannas, and Shrublands. The classification of 5-day sequences of mid-tropospheric circulation indicates that a persistent trough of low-pressure over Alaska and the North Pacific is the dominant pattern preceding mid-winter break-ups. Furthermore, the trough is stronger for events in British Columbia and Alberta compared with Alaska and the Yukon. The results of this research improve our understanding of the hydro-climatic conditions that generate mid-winter break-up events in western Canada and Alaska and will aid in the prediction and risk management of such events.

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