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2021 ◽  
Author(s):  
Tyler A. Grambling ◽  
et al.

Methods details; Table S1 (sample isotopic, depth, and location information); Table S2 (deformation temperatures); Table S3 (paleoelevation model results); and Table S4 (recharge elevation model results from modern water samples).<br>


2021 ◽  
Author(s):  
Tyler A. Grambling ◽  
et al.

Methods details; Table S1 (sample isotopic, depth, and location information); Table S2 (deformation temperatures); Table S3 (paleoelevation model results); and Table S4 (recharge elevation model results from modern water samples).<br>


2021 ◽  
Author(s):  
Jian Zhang ◽  
Yonggang Liu ◽  
Xiaomin Fang ◽  
Tao Zhang ◽  
Chenguang Zhu ◽  
...  

&lt;p&gt;The Tibetan Plateau has a significant impact on the Asian climate due to its high topography. However, its uplift history, especially the uplift of the Gangdese Mountains in its early stage, is under intense debate. Most quantitative reconstructions are done for the Cenozoic only, impeding our understanding of the geodynamic and paleoenvironmental evolution during the Cretaceous. How high would the Gangdese Mountains be then, and what effects would they have on Asian climate? In order to explore these two questions, here we model the impacts of the Gangdese Mountains on the Asian climate during the Late Cretaceous by employing the Community Earth System Model version 1.2.2. It is found that the extent of dry land in East Asia is sensitive to the altitude of the Gangdese Mountains; it expands eastwards and southwards with the rise of the mountain range, which is due to the fact that the Gangdese Mountains can significantly reduce the precipitation over the low- to mid-latitude Asia. We then attempt to constrain their paleoaltitude using the available climate indicators in the sediments. The aridity index is further calculated for this region, and its comparison with the climate records suggests that Gangdese Mountains should be higher than 1 km but lower than 3 km during the Late Cretaceous, most likely ~2 km.&lt;/p&gt;


2021 ◽  
Author(s):  
Laura Owen ◽  
Jennifer Catto ◽  
David Stephenson ◽  
Nick Dunstone

&lt;p&gt;Extreme precipitation and winds can have a severe impact on society, particularly when they occur at the same place and time. Studies have investigated the frequency of co-occurring extreme precipitation and wind using observational data. However, due to the rarity of very extreme events, these results are limited, since a large number of samples is needed to get robust estimates. Additionally, it is very difficult for estimates based on observations alone to help us understand the risk of future unprecedented events. Using the UNSEEN method (UNprecedented Simulated Extremes using ENsembles) this risk can be estimated from large ensembles of climate simulations. The Met Office's Global Seasonal forecast system version 5 (GloSea5) model ensembles are evaluated against ERA5 reanalysis data to find out how well they represent extreme precipitation, extreme wind and extreme co-occurring events over Europe. This model has not been evaluated in such a way before and this is needed before the model can be used to estimate the likelihood of unprecedented events using the UNSEEN method. We find that although the intensity of precipitation and wind extremes differ between the model and observations (by up to 12 mm and 9 m/s), the frequency of co-occurring events is well represented. The extremal dependency measure, &amp;#967;, which measures co-occurrence, compares well spatially over Europe between GloSea5 and ERA5. However, significant differences in &amp;#967; are found over areas of high topography, over the North Atlantic, Western Europe and the Norwegian Sea. Generally, GloSea5 underestimates &amp;#967; over the ocean, and performs better over land. Mean sea level pressure anomaly composites for co-occurring extreme events show that at a number of selected locations, the co-occurring extremes are produced by very similar synoptic situations in the model and reanalysis. This gives increased confidence in the model. The model ensembles can then be used to assess the present day likelihood of unprecedented 3 hourly compound precipitation and wind extremes for winter over Europe, and to find out how the NAO index influences the frequency of co-occurring events over Europe.&lt;/p&gt;


Author(s):  
Brian Watson ◽  
Shlomit Katz ◽  
Richard Housley ◽  
Kar Wui Thong ◽  
Roy Nikhil Aditya Kumar ◽  
...  
Keyword(s):  

2020 ◽  
Author(s):  
Andries Jan De Vries

Abstract. Extreme precipitation events (EPEs) cause frequently flooding with dramatic socioeconomic impacts in many parts of the world. Previous studies considered two synoptic-scale processes, Rossby wave breaking and intense moisture transport, typically in isolation, and their linkage to such EPEs in several regions. This study presents for the first time a global and systematic climatological analysis of these two synoptic-scale processes, in tandem and in isolation, for the occurrence of EPEs. To this end, we use 40-year ERA-Interim reanalysis data (1979–2018) and apply object-based identification methods for (i) daily EPEs, (ii) stratospheric potential vorticity (PV) streamers as indicators of Rossby wave breaking, and (iii) structures of high vertically integrated horizontal water vapor transport (IVT). First, the importance of these two processes is demonstrated by case studies of previously documented flood events that inflicted catastrophic impacts in different parts of the world. Next, a climatological quantification shows that Rossby wave breaking is associated with > 90 % of EPEs near high topography and over the Mediterranean, intense moisture transport is linked to > 90 % of EPEs over many coastal zones, and their combined occurrence contributes to > 70 % of EPEs in several subtropical and extratropical regions. A more detailed analysis shows that a majority of EPEs associated with (1) only Rossby wave breaking are confined to higher-latitude regions that are deprived from remote moisture supplies by high topography and deserts, (2) only intense moisture transport are found circumglobally at the outer tropics, associated with tropical cyclones, tropical easterly waves, and monsoon lows, (3) combined Rossby wave breaking and intense moisture transport dominate a large part of the globe, in particular over dry subtropical regions where tropical-extratropical interactions are of key relevance, (4) remote, far upstream Rossby wave breaking and intense moisture transport occur over mountainous extratropical west coasts, reminiscent of landfalling atmospheric rivers, and (5) neither of the two synoptic-scale processes are concentrated over the inner tropics and high topography at lower latitudes, where EPEs arise under the influence of local forcing. Accordingly, different combinations of wave breaking and intense moisture transport can reflect a large range of weather systems with relevance to EPEs across various climate zones. Furthermore, the relationship between the PV and IVT characteristics and the precipitation volumes shows that the strength of the wave breaking and moisture transport intensity are intimately connected with the extreme precipitation severity. Finally, composites reveal that subtropical and extratropical EPEs, linked to Rossby wave breaking, go along with the formation of upper-level troughs and cyclogenetic processes near the surface downstream, reduced static stability beneath the upper-level forcing (only over water), and dynamical lifting ahead (over water and land). This study concludes with a concept that reconciles well-established meteorological principles with the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events. The findings of this study may contribute to an improved understanding of the atmospheric processes that lead to EPEs, and may find application in climatic studies on extreme precipitation changes in a warming climate.


2020 ◽  
Vol 125 (9) ◽  
Author(s):  
Babak Hejrani ◽  
Niels Balling ◽  
Bo Holm Jacobsen ◽  
Søren Bom Nielsen

Author(s):  
Thomas Triadi Putranto ◽  
Novie Susanto ◽  
Dina Rahayuning Pangestuti ◽  
Mathias Andika Setya Pranata

Groundwater management at groundwater basins Sumowono needs to be done because of the increasing development of the area. This research is oriented to analyzing groundwater conditions, compiling groundwater conservation zones, and explaining conservation zones' suitability with spatial maps. The method used is mapping hydrogeological conditions such as surface observation of rock types, inventory of hydrogeological points of interest, knowing the patterns and directions of groundwater flow, groundwater utilization, and groundwater sampling to measure the degree of acidity and electrical conductivity. From the mapping results, it is found that the lithology is composed of tuffaceous sandstones and volcanic breccias. Based on the free groundwater table analysis, the free groundwater flow pattern follows the topographic slope, flowing from the high topography on the south and southeast sides to the low topography on the north side of the area. The utilization of groundwater is used for irrigation, domestic and fishery purposes. Measurement of groundwater samples' quality for the degree of acidity is between 5.32-7.98 while the electrical conductivity is between 36-550 µS / cm, and the level of damage due to groundwater utilization is included in the safe zone. The groundwater conservation zone consists of recharge areas and spring protection zones. The result of overlapping between the groundwater conservation zone and the spatial plan map shows suitability as a protection zone.


Geosphere ◽  
2020 ◽  
Vol 16 (4) ◽  
pp. 919-935
Author(s):  
William J. Cochran ◽  
James A. Spotila ◽  
Philip S. Prince

Abstract The nature of the connection between the Eastern California shear zone (ECSZ) and the San Andreas fault (SAF) in southern California (western United States) is not well understood. Northwest of San Gorgonio Pass, strands of the ECSZ may be migrating south and west into the convergent zone of the San Bernardino Mountains (SBM) as it is advected to the southeast via the SAF. Using high-resolution topography and field mapping, this study aims to test whether diffuse faults within the SBM represent a nascent connection between the ECSZ and the SAF. Topographic resolution of ≤1 m was achieved using both lidar and unmanned aerial vehicle surveys along two Quaternary strike-slip faults. The Lone Valley fault enters the SBM from the north and may form an along-strike continuation of the Helendale fault. We find that its geomorphic expression is obscured where it crosses Quaternary alluvium, however, suggesting that it may have a low rate of yet-undetermined activity. The Lake Peak fault is located farther south and cuts through the high topography of the San Gorgonio massif and may merge with strands of the SAF system. We find that this fault clearly cuts Quaternary glacial deposits, although the magnitude of offset is difficult to assess. Based on our interpretation of geomorphic features, we propose that the Lake Peak fault has predominantly dextral or oblique-dextral motion, possibly with a slip rate that is comparable to the low rates observed along other strands of the ECSZ (i.e., ≤1 mm/yr). Comparing the geomorphic expressions of these faults is difficult, however, given that the erosive nature of the mountainous landscape in the SBM may obscure evidence of active faulting. Based on these observations, as well as the occurrence of other diffuse faults in the region, we suggest that dextral strain is overprinting the actively convergent zone of the SBM, thereby creating a throughgoing connection between the ECSZ and the SAF west of San Gorgonio Pass.


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