The New Zealand Southern Alps Experiment

Wratt, David; Ridley, R. N.; Sinclair, Mark R.; Larsen, Howard; Thompson, S. M.; Henderson, Roddy; Austin, G. L.; Bradley, Stuart; Auer, Andreea; Sturman, Andrew; Owens, I. F.; Fitzharris, B. B.; Ryan, B. F.; Gayet, J.-F.

doi:10.1175/1520-0477(1996)077<0683:tnzsae>2.0.co;2

Cited by 66 publications

(41 citation statements)

References 11 publications

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“…This is particularly true for the highest mountain range, the Southern Alps, but lower mountain ranges in the North Island consistently stand out too. With the eastern part of the South Island often experiencing föhn winds (Wratt et al, 1996;Sturman and Tapper, 2006), the generally warmer temperatures in the east in the RCM are probably caused by an enhanced 'föhn' effect in the model. This is particularly 1158 F. DROST ET AL.…”

Section: Temperaturementioning

confidence: 99%

Simulation of New Zealand's climate using a high‐resolution nested regional climate model

Drost

Renwick

Bhaskaran

et al. 2006

Intl Journal of Climatology

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Abstract:A regional climate model (RCM) for New Zealand has been developed. The RCM is embedded within a GCM and both models are run under pre-industrial conditions. Seasonal mean output of the RCM is compared against NCEP data and the New Zealand national climate database. Regional and seasonal aspects of modelled surface temperature and precipitation are to a large extent simulated correctly. The main anomalies are related to the difficulty of incorporating New Zealand's orography appropriately and to the initial and lateral boundary conditions, which were supplied by the GCM. The largest anomalies occur over the Southern Alps, where the modelled temperatures are too low and where the amount of precipitation is too high. Many parts of the east coasts in both the North and South Island are too warm and too dry. Correlation patterns of temperature and precipitation with mean sea-level pressure differ considerably from the equivalent patterns constructed from NCEP data, but do show in general the dominant relationships between wind direction and temperature and precipitation.

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Section: Temperaturementioning

confidence: 99%

Simulation of New Zealand's climate using a high‐resolution nested regional climate model

Drost

Renwick

Bhaskaran

et al. 2006

Intl Journal of Climatology

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“…Their studies, as well as forecaster experience (Morss and Ralph 2007), have noted the importance of the low-level jet (LLJ) ahead of the primary cold front in these storms in terms of predicting floods in California. Earlier studies in Europe and New Zealand (Wratt et al 1996) centered on the warm sector and the LLJ in focusing orographic precipitation (e.g., Browning et al 1974) and in creating damaging winds (Crochet et al 1990). This region of the storm has now been recognized as representing AR conditions, and since the frontal waves modulate the characteristics of the front and its associated AR (position, strength, propagation, vertical motion), it is crucial to determine which watersheds are likely to flood (Ralph et al 2003;Andrews et al 2004).…”

Section: Introductionmentioning

confidence: 99%

A Multiscale Observational Case Study of a Pacific Atmospheric River Exhibiting Tropical–Extratropical Connections and a Mesoscale Frontal Wave

et al. 2011

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A case study is presented of an atmospheric river (AR) that produced heavy precipitation in the U.S. Pacific Northwest during March 2005. The study documents several key ingredients from the planetary scale to the mesoscale that contributed to the extreme nature of this event. The multiscale analysis uses unique experimental data collected by the National Oceanic and Atmospheric Administration (NOAA) P-3 aircraft operated from Hawaii, coastal wind profiler and global positioning system (GPS) meteorological stations in Oregon, and satellite and global reanalysis data. Moving from larger scales to smaller scales, the primary findings of this study are as follow: 1) phasing of several major planetary-scale phenomena influenced by tropical-extratropical interactions led to the direct entrainment of tropical water vapor into the AR near Hawaii, 2) dropsonde observations documented the northward advection of tropical water vapor into the subtropical extension of the midlatitude AR, and 3) a mesoscale frontal wave increased the duration of AR conditions at landfall in the Pacific Northwest.

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“…Orographic precipitation in Australia has received little attention in comparison to mountainous regions of Europe (e.g., Rotunno and Houze 2007;Volkert and Gutermann 2007), North America (e.g., Stoelinga et al 2003;Ikeda et al 2007), and New Zealand (Wratt et al 1996), where intensive observational studies have been conducted with the aim of characterizing surface precipitation distribution and improving microphysical parameterizations, among other things. This is perhaps understandable, given that the contribution of orographic precipitation to the Australian annual total is relatively small, because of the relatively low profile of the Great Dividing Range and the absence of a nearby warm moisture source upwind of the range.…”

Section: Introductionmentioning

confidence: 99%

On the Decline of Wintertime Precipitation in the Snowy Mountains of Southeastern Australia

Chubb

Siems

Manton

2011

Journal of Hydrometeorology

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Data from a precipitation gauge network in the Snowy Mountains of southeastern Australia have been analyzed to produce a new climatology of wintertime precipitation and airmass history for the region in the period 1990-2009. Precipitation amounts on the western slopes and in the high elevations (.1000 m) of the Snowy Mountains region have experienced a decline in precipitation in excess of the general decline in southeastern Australia. The contrast in the decline east and west of the ranges suggests that factors influencing orographic precipitation are of particular importance. A synoptic decomposition of precipitation events has been performed, which demonstrates that about 57% of the wintertime precipitation may be attributed to storms associated with ''cutoff lows'' (equatorward of 458S). A further 40% was found to be due to ''embedded lows,'' with the remainder due to Australian east coast lows and several other sporadically occurring events. The declining trend in wintertime precipitation over the past two decades is most clearly seen in the intensity of precipitation due to cutoff lows and coincides with a decline in the number of systems associated with a cold frontal passage. Airmass history during precipitation events was represented by back trajectories calculated from ECMWF Interim Reanalysis data, and statistics of air parcel position were related to observations of precipitation intensity. This approach gives insight into sources of moisture during wintertime storms, identifying ''moisture corridors,'' which are typically important for transport of water vapor from remote sources to the Snowy Mountains region. The prevalence of these moisture corridors is associated with the southern annular mode, which corresponds to fluctuations in the strength of the westerly winds in southeastern Australia.

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The New Zealand Southern Alps Experiment

Cited by 66 publications

References 11 publications

Simulation of New Zealand's climate using a high‐resolution nested regional climate model

Simulation of New Zealand's climate using a high‐resolution nested regional climate model

A Multiscale Observational Case Study of a Pacific Atmospheric River Exhibiting Tropical–Extratropical Connections and a Mesoscale Frontal Wave

On the Decline of Wintertime Precipitation in the Snowy Mountains of Southeastern Australia

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