Spatial and temporal variability of East African Kiremt season precipitation and large‐scale teleconnections

2019 ◽  
Vol 40 (2) ◽  
pp. 1241-1254 ◽  
Author(s):  
Daniel Broman ◽  
Balaji Rajagopalan ◽  
Thomas Hopson ◽  
Mekonnen Gebremichael
Keyword(s):  
Temporal Variability ◽  
Large Scale ◽  
Spatial And Temporal Variability ◽  
East African

Large-Scale Atmospheric Drivers of Snowfall on Thwaites Glacier

2020 ◽  
Author(s):  
Michelle Maclennan ◽  
Jan Lenaerts
Keyword(s):  
Temporal Variability ◽  
Large Scale ◽  
Climate Model ◽  
Southern Oscillation ◽  
Regional Climate ◽  
Southern Annular Mode ◽  
Spatial And Temporal Variability ◽  
Atmospheric Conditions ◽  
Amundsen Sea ◽  
Weather Patterns

<p>High snowfall events on Thwaites Glacier are a key influencer of its ice mass change. In this study, we diagnose the mechanisms for orographic precipitation on Thwaites Glacier by analyzing the atmospheric conditions that lead to high snowfall events. A high-resolution regional climate model, RACMO2, is used in conjunction with MERRA-2 and ERA5 reanalysis to map snowfall and associated atmospheric conditions over the Amundsen Sea Embayment. We examine these conditions during high snowfall events over Thwaites Glacier to characterize the drivers of the precipitation and their spatial and temporal variability. Then we examine the seasonal differences in the associated weather patterns and their correlations with El Nino Southern Oscillation and the Southern Annular Mode. Understanding the large-scale atmospheric drivers of snowfall events allows us to recognize how these atmospheric drivers and consequent snowfall climatology will change in the future, which will ultimately improve predictions of accumulation on Thwaites Glacier.</p>

scholarly journals Modes of Vertical Thermodynamic and Wind Variability over the Maritime Continent

2016 ◽  
Author(s):  
Jennie Bukowski ◽  
Derek J. Posselt ◽  
Jeffrey S. Reid ◽  
Samuel A. Atwood
Keyword(s):  
Temporal Variability ◽  
Large Scale ◽  
Principal Component ◽  
Structure Functions ◽  
Dimensional Subspace ◽  
Radiosonde Data ◽  
Spatial And Temporal Variability ◽  
Convective Systems ◽  
Wind Variability ◽  
Wind Profiles

Abstract. The Maritime Content (MC) is an exceedingly complex region, both from the perspective of its meteorology and its aerosol characteristics. Convection in the MC is ubiquitous, and assumes a wide variety of forms under the influence of an evolving large scale dynamic and thermodynamic context. Understanding the interaction between convective systems and their environment, both individually and in the aggregate, requires knowledge of the dominant patterns of spatial and temporal variability. To this end, radiosonde observations from 2008–2016 are examined from three sounding release sites within the MC for the purpose of exploring the dominant vertical temperature, humidity, and wind structures in the region. Principal Component Analysis is applied to the vertical atmospheric column to transform patterns present in radiosonde data into canonical thermodynamic and wind profiles for the MC. Both rotated and non-rotated principal components are considered, and the emerging structure functions reflect the fundamental vertical modes of short-term tropical variability. The results indicate that while there is tremendous spatial and temporal variability across the MC, the primary modes of vertical thermodynamic and wind variability in the region can be represented in a lower-dimensional subspace. In addition, the vertical structures are very similar among different sites around the region, though different structures may manifest more strongly at one location than another. The results indicate that, while very different meteorology may be found in various parts of the MC at any given time, the processes themselves are remarkably consistent. The ability to represent this variability using a limited number of structure functions facilitates analysis of co-variability between atmospheric structure and convective systems, and also enables future systematic model-based ensemble analysis of cloud development, convection, and precipitation over the MC.

scholarly journals Spatial and Temporal Variability in Rainfall Erosivity Under Alpine Climate: A Slovenian Case Study Using Optical Disdrometer Data

2021 ◽  
Vol 9 ◽  
Author(s):  
Nejc Bezak ◽  
Sašo Petan ◽  
Matjaž Mikoš
Keyword(s):  
Temporal Variability ◽  
Large Scale ◽  
Annual Rainfall ◽  
Mean Annual Precipitation ◽  
Rainfall Erosivity ◽  
Spatial And Temporal Variability ◽  
Strongly Correlated ◽  
Erosion Rates ◽  
Precipitation Events

Rainfall erosivity is one of the most important parameters that influence soil erosion rates. It is characterized by a large spatial and temporal variability. For example, in Slovenia, which covers around 20,000 km2, the annual rainfall erosivity ranges from less than 1,000 MJ mm ha−1 h−1 to more than 10,000 MJ mm ha−1 h−1. Drop size distribution (DSD) data are needed to investigate rainfall erosivity characteristics. More than 2 years of DSD measurements using optical disdrometers located at six stations in Slovenia were used to investigate the spatial and temporal variability in rainfall erosivity in Slovenia. Experimental results have indicated that elevation is a poor predictor of rainfall erosivity and that erosivity is more strongly correlated to the mean annual precipitation. Approximately 90% of the total kinetic energy (KE) was accounted for in about 35% of 1 min disdrometer data. The highest 1 min intensities (I) and consequently also KE values were measured in summer followed by autumn and spring. The local KE-I equation yielded an acceptable fit to the measured data in case of all six stations. The relatively large percentage of 1 min rainfall intensities above 5 mm/h can at least partially explain some very high annual rainfall erosivity values (i.e., near or above 10,000 MJ mm ha−1 h−1). Convective and large-scale precipitation events also result in various rainfall erosivity characteristics. The station microlocation and wind impacts in case of some stations yielded relatively large differences between the data measured using the optical disdrometer and the pluviograph. Preliminary conclusions have been gathered, but further measurements are needed to get even better insight into spatial and temporal variability in rainfall erosivity under Alpine climate in Slovenia.

scholarly journals Connecting European snow cover variability with large scale atmospheric patterns

2010 ◽  
Vol 26 ◽  
pp. 93-97 ◽  
Author(s):  
E. Bartolini ◽  
P. Claps ◽  
P. D'Odorico
Keyword(s):  
Climate Variability ◽  
Snow Cover ◽  
Temporal Variability ◽  
Large Scale ◽  
Management Strategies ◽  
The Other ◽  
The Arctic ◽  
Spatial And Temporal Variability ◽  
East Atlantic ◽  
The North

Abstract. Winter snowfall and its temporal variability are important factors in the development of water management strategies for snow-dominated regions. For example, mountain regions of Europe rely on snow for recreation, and on snowmelt for water supply and hydropower. It is still unclear whether in these regions the snow regime is undergoing any major significant change. Moreover, snow interannual variability depends on different climatic variables, such as precipitation and temperature, and their interplay with atmospheric and pressure conditions. This paper uses the EASE Grid weekly snow cover and Ice Extent database from the National Snow and Ice Data Center to assess the possible existence of trends in snow cover across Europe. This database provides a representation of snow cover fields in Europe for the period 1972–2006 and is used here to construct snow cover indices, both in time and space. These indices allow us to investigate the historical spatial and temporal variability of European snow cover fields, and to relate them to the modes of climate variability that are known to affect the European climate. We find that both the spatial and temporal variability of snow cover are strongly related to the Arctic Oscillation during wintertime. In the other seasons, weaker correlation appears between snow cover and the other patterns of climate variability, such as the East Atlantic, the East Atlantic West Russia, the North Atlantic Oscillation, the Polar Pattern and the Scandinavian Pattern.

scholarly journals Spatial and temporal variability of climate extremes in Romania and associated large‐scale mechanisms

2014 ◽  
Vol 35 (7) ◽  
pp. 1278-1300 ◽  
Author(s):  
Aristita Busuioc ◽  
Andreea Dobrinescu ◽  
Marius‐Victor Birsan ◽  
Alexandru Dumitrescu ◽  
Alina Orzan
Keyword(s):  
Temporal Variability ◽  
Large Scale ◽  
Climate Extremes ◽  
Spatial And Temporal Variability

scholarly journals Spatial and temporal variability of snow accumulation rate on the East Antarctic ice divide between Dome Fuji and EPICA DML

2011 ◽  
Vol 5 (4) ◽  
pp. 1057-1081 ◽  
Author(s):  
S. Fujita ◽  
P. Holmlund ◽  
I. Andersson ◽  
I. Brown ◽  
H. Enomoto ◽  
...  
Keyword(s):  
Surface Topography ◽  
Temporal Variability ◽  
Large Scale ◽  
Accumulation Rate ◽  
Snow Accumulation ◽  
Leeward Side ◽  
Spatial And Temporal Variability ◽  
Strong Wind ◽  
Surface Mass ◽  
Wind Events

Abstract. To better understand the spatio-temporal variability of the glaciological environment in Dronning Maud Land (DML), East Antarctica, a 2800-km-long Japanese-Swedish traverse was carried out. The route includes ice divides between two ice-coring sites at Dome Fuji and EPICA DML. We determined the surface mass balance (SMB) averaged over various time scales in the late Holocene based on studies of snow pits and firn cores, in addition to radar data. We find that the large-scale distribution of the SMB depends on the surface elevation and continentality, and that the SMB differs between the windward and leeward sides of ice divides for strong-wind events. We suggest that the SMB is highly influenced by interactions between the large-scale surface topography of ice divides and the wind field of strong-wind events that are often associated with high-precipitation events. Local variations in the SMB are governed by the local surface topography, which is influenced by the bedrock topography. In the eastern part of DML, the accumulation rate in the second half of the 20th century is found to be higher by ~15 % than averages over longer periods of 722 a or 7.9 ka before AD 2008. A similar increasing trend has been reported for many inland plateau sites in Antarctica with the exception of several sites on the leeward side of the ice divides.

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