scholarly journals Floods in the Southern Alps of New Zealand: the importance of atmospheric rivers

2016 ◽  
Vol 30 (26) ◽  
pp. 5063-5070 ◽  
Author(s):  
Daniel. G. Kingston ◽  
David A. Lavers ◽  
David M. Hannah
Keyword(s):  
New Zealand ◽  
Southern Alps ◽  
Atmospheric Rivers

The Role of Atmospheric Rivers for Extreme Ablation and Snowfall Events in the Southern Alps of New Zealand

2019 ◽  
Vol 46 (5) ◽  
pp. 2761-2771 ◽  
Author(s):  
K. Little ◽  
D. G. Kingston ◽  
N. J. Cullen ◽  
P. B. Gibson
Keyword(s):  
New Zealand ◽  
Southern Alps ◽  
Atmospheric Rivers

Moisture transport during large snowfall events in the New Zealand Southern Alps: The role of atmospheric rivers

2020 ◽  
Author(s):  
Rasool Porhemmat ◽  
Heather Purdie ◽  
Peyman Zawar-Reza ◽  
Christian Zammit ◽  
Tim Kerr
Keyword(s):  
New Zealand ◽  
Moisture Transport ◽  
Reanalysis Data ◽  
Southern Alps ◽  
Water Vapour Flux ◽  
Atmospheric Rivers ◽  
Transport Dynamics ◽  
Wind Velocities ◽  
Vapour Flux ◽  
Depth Increase

AbstractSynoptic-scale moisture transport during large snowfall events in the New Zealand Southern Alps is largely unknown due to a lack of long-term snow observations. In this study, records from three recently developed automatic weather stations (Mahanga, Mueller Hut and Mt Larkins) near the Main Divide of the Southern Alps were used to identify large snowfall events between 2010 and 2018. The large snowfall events are defined as those events with daily snow depth increase by greater than the 90th percentile at each site. ERA-Interim reanalysis data were used to characterize the hydrometeorological features of the selected events. Our findings show that large snowfall events in the Southern Alps generally coincide with strong fields of integrated vapour transport (IVT) within a north-westerly airflow and concomitant deepening low pressure systems. Considering the frequency of large snowfall events, approximately 61% of such events at Mahanga were associated with narrow corridors of strong water vapour flux, known as atmospheric rivers (ARs). The contributions of ARs to the large snowfall events at Mueller Hut and Mt Larkins were 70% and 71%, respectively. Analysis of the vertical profiles of moisture transport dynamics during the passage of a landfalling AR during 11-12th October 2016 revealed the key characteristics of a snow-generating AR in the Southern Alps. An enhanced presence of low and mid-level moisture between 700-850 hPa and pronounced increases of wind velocities (more than 30 m s-1) with high values of the meridional component between 750-850 hPa were identified over the Southern Alps during the event.

Gold mineralisation near the Main Divide, upper Wilberforce valley, Southern Alps, New Zealand

2000 ◽  
Vol 43 (2) ◽  
pp. 199-215 ◽  
Author(s):  
J. A. Becker ◽  
D. Craw ◽  
T. Horton ◽  
C. P. Chamberlain
Keyword(s):  
New Zealand ◽  
Southern Alps

Erosion rates of the New Zealand Southern Alps reflect long-term tectonics and transient climate

2021 ◽  
Author(s):  
Duna Roda-Boluda ◽  
Taylor Schildgen ◽  
Hella Wittmann-Oelze ◽  
Stefanie Tofelde ◽  
Aaron Bufe ◽  
...  
Keyword(s):  
New Zealand ◽  
Strike Slip ◽  
Southern Alps ◽  
Fault System ◽  
Tectonic Deformation ◽  
Seismic Cycle ◽  
Erosion Rates ◽  
Alpine Fault ◽  
Oblique Convergence

<p>The Southern Alps of New Zealand are the expression of the oblique convergence between the Pacific and Australian plates, which move at a relative velocity of nearly 40 mm/yr. This convergence is accommodated by the range-bounding Alpine Fault, with a strike-slip component of ~30-40 mm/yr, and a shortening component normal to the fault of ~8-10 mm/yr. While strike-slip rates seem to be fairly constant along the Alpine Fault, throw rates appear to vary considerably, and whether the locus of maximum exhumation is located near the fault, at the main drainage divide, or part-way between, is still debated. These uncertainties stem from very limited data characterizing vertical deformation rates along and across the Southern Alps. Thermochronology has constrained the Southern Alps exhumation history since the Miocene, but Quaternary exhumation is hard to resolve precisely due to the very high exhumation rates. Likewise, GPS surveys estimate a vertical uplift of ~5 mm/yr, but integrate only over ~10 yr timescales and are restricted to one transect across the range.</p><p>To obtain insights into the Quaternary distribution and rates of exhumation of the western Southern Alps, we use new <sup>10</sup>Be catchment-averaged erosion rates from 20 catchments along the western side of the range. Catchment-averaged erosion rates span an order of magnitude, between ~0.8 and >10 mm/yr, but we find that erosion rates of >10 mm/yr, a value often quoted in the literature as representative for the entire range, are very localized. Moreover, erosion rates decrease sharply north of the intersection with the Marlborough Fault System, suggesting substantial slip partitioning. These <sup>10</sup>Be catchment-averaged erosion rates integrate, on average, over the last ~300 yrs. Considering that the last earthquake on the Alpine Fault was in 1717, these rates are representative of inter-seismic erosion. Lake sedimentation rates and coseismic landslide modelling suggest that long-term (~10<sup>3</sup> yrs) erosion rates over a full seismic cycle could be ~40% greater than our inter-seismic erosion rates. If we assume steady state topography, such a scaling of our <sup>10</sup>Be erosion rate estimates can be used to estimate rock uplift rates in the Southern Alps. Finally, we find that erosion, and hence potentially exhumation, does not seem to be localized at a particular distance from the fault, as some tectonic and provenance studies have suggested. Instead, we find that superimposed on the primary tectonic control, there is an elevation/temperature control on erosion rates, which is probably transient and related to frost-cracking and glacial retreat.</p><p>Our results highlight the potential for <sup>10</sup>Be catchment-averaged erosion rates to provide insights into the magnitude and distribution of tectonic deformation rates, and the limitations that arise from transient erosion controls related to the seismic cycle and climate-modulated surface processes.</p><p> </p><p> </p>

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