Zealand Glaciers Research Articles

The Tourism Adaptation Classification (TAC) framework: An application to New Zealand's Glacier country

Alongside growing awareness of the significance of environmental change for glacier regions, and their tourism-dependent communities, is the realization of the need to adapt to changing conditions. Such adaptation is necessary for tourism operators, managers, and planners as well as the visitors themselves, and is part of building resilient tourism systems. This paper presents a conceptual framework for understanding the possible stages of adaptation in glacier tourism destinations. The Tourism Adaptation Classification (TAC) framework aligns three stages of adaptation (resilience, transition, and transformation) against adaptation strategies implemented by tourism stakeholders and identifies specific characteristics. Using a desk-based case study approach, the framework is illustrated with reference to Glacier Country in New Zealand's Westland/Tai Poutini National Park in relation to three core dimensions of the tourism system: tourism planning and governance; tourism business and operations; and visitor experience.

Multiple glacial maxima of similar extent at ∼20–45 ka on Mt. Usborne, East Falkland, South Atlantic region

The pattern, timing, and origin of Southern Hemisphere climate change during the last glaciation remains a pressing problem, with implications for the role of orbital forcing in ice-age cycles. Here, we present geomorphological and cosmogenic exposure age data from East Falkland in the South Atlantic region that show onset of glacial conditions by marine isotope stage 4 (∼60–70 ka), with expansion of ice to its maximum extent of the last glaciation. At least seven geomorphological units marked by multiple crests on composite moraines indicate glacier expansion on Mt. Usborne, the highest peak of East Falkland. From ∼20 to 45 ka, glaciers fluctuated on a millennial timescale with near-maximum conditions being reached repeatedly. Overall ice extent appears to have shrunk slightly through time, with evidence of glaciation at ∼20 ka preserved only in the highest-elevation cirques. This long glacial maximum is inconsistent both with local orbital control and orbital forcing as expressed in the traditional Milankovitch hypothesis. The timing of millennial glacier expansions occurred between Northern Hemisphere Heinrich Stadials and resembles that documented for New Zealand glaciers, suggesting at least a trans-Pacific expression. We postulate that periodic recessions corresponded with southward expansion of the southern westerlies during Heinrich Stadials and warming air and ocean temperatures over the South Atlantic region.

Variability in glacier albedo and links to annual mass balance for the gardens of Eden and Allah, Southern Alps, New Zealand

Abstract. The gardens of Eden and Allah (GoEA) are two of New Zealand's largest ice fields. However, their remote location and protected conservation status have limited access and complicated monitoring and research efforts. To improve our understanding of the spatial and temporal changes in mass balance of these unique ice fields, observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors are used to monitor annual minimum glacier-wide albedo (α¯yrmin) over the period 2000–2018. The α¯yrmin for 12 individual glaciers ranges between 0.42 and 0.70 and can occur as early as mid-January and as late as the end of April. The evolution of the timing of α¯yrmin indicates a shift to later in the summer over the 19-year period on 10 of the 12 glaciers. However, there is only a weak relationship between the delay in timing and the magnitude of α¯yrmin, which implies that albedo is not necessarily lower if it is delayed. The largest negative departures in α¯yrmin (lower-than-average albedo) are consistent with high snowline altitudes (SLAs) relative to the long-term average as determined from the End of Summer Snowline (EOSS) survey, which has been the benchmark for monitoring glaciers in the Southern Alps for over 40 years. While the record of α¯yrmin for Vertebrae Col 25, an index glacier of the EOSS survey and one of the GoEA glaciers, explains less than half of the variability observed in the corresponding EOSS SLA (R2=0.43, p=0.003), the relationship is stronger when compared to other GoEA glaciers. Angel Glacier has the strongest relationship with EOSS observations at Vertebrae Col 25, accounting for 69 % of its variance (p<0.001). A key advantage in using the α¯yrmin approach is that it enables variability in the response of individual glaciers to be explored, revealing that topographic setting plays a key role in addition to the regional climate signal. The observed variability in individual glacier response at the scale of the GoEA contrasts with the high consistency of responses found by the EOSS record across the Southern Alps and challenges the suggestion that New Zealand glaciers behave as a unified climatic unit. MODIS imagery acquired from the Terra and Aqua platforms also provides insights about the spatial and temporal variability in clouds. The frequency of clouds in pixels west of the Main Divide is as high as 90 % during summer months and reaches a minimum of 35 % in some locations in winter. These complex cloud interactions deserve further attention as they are likely a contributing factor in controlling the spatial and temporal variability in glacier response observed in the GoEA.

Updated inventory of glacier ice in New Zealand based on 2016 satellite imagery

AbstractThe only complete inventory of New Zealand glaciers was based on aerial photography starting in 1978. While there have been partial updates using 2002 and 2009 satellite data, most glaciers are still represented by the 1978 outlines in contemporary global glacier databases. The objective of this project is to establish an updated glacier inventory for New Zealand. We have used Landsat 8 OLI satellite imagery from February and March 2016 for delineating clean glaciers using a semi-automatic band ratio method and debris-covered glaciers using a maximum likelihood classification. The outlines have been checked against Sentinel-2 MSI data, which have a higher resolution. Manual post processing was necessary due to misclassifications (e.g. lakes, clouds), mapping in shadowed areas, and combining the clean and debris-covered parts into single glaciers. New Zealand glaciers cover an area of 794 ± 34 km2 in 2016 with a debris-covered area of 10%. Of the 2918 glaciers, seven glaciers are >10 km2 while 71% is <0.1 km2. The debris cover on those largest glaciers is >40%. Only 15 glaciers are located on the North Island. For a selection of glaciers, we were able to calculate the area reduction between the 1978 and 2016 inventories.

Extreme glacier melt and climate change

Extreme melt years are occurring more often than ever for glaciers around the world. We make it possible to measure the impact of climate change on this melt. We show that the extreme melt of New Zealand glaciers in 2018 was at least ten times more likely to have happened as a result of climate change. - submission by Lauren J. Vargo

The MIS 3 maximum of the Torres del Paine and Última Esperanza ice lobes in Patagonia and the pacing of southern mountain glaciation

The timing, structure and termination of the last southern mountain glaciation and its forcing remains unclear. Most studies have focused on the global Last Glacial Maximum (LGM; 26.5–19 ka) time period, which is just part of the extensive time-frame within the last glacial period, including Marine Isotope Stages 3 and 4. Understanding the glacial fluctuations throughout the glacial period is a prerequisite for uncovering the cause and climate mechanism driving southern glaciation and the interhemispheric linkages of climate change. Here, we present an extensive (n = 65) cosmogenic 10Be glacier chronology derived from moraine belts marking the pre-global LGM extent of the former Patagonian Ice Sheet in southernmost South America. Our results show the mountain ice sheet reached its maximum extent at 48.0 ± 1.8 ka during the local LGM, but attained just half this extent at 21.5 ± 1.8 ka during the global LGM. This finding, supported by nearby glacier chronologies, indicates that at orbital time scales, the southern mid-latitude glaciers fluctuated out-of-phase with northern hemisphere ice sheets. At millennial time-scales, our data suggest that Patagonian and New Zealand glaciers advanced in unison with cold Antarctic stadials and reductions in Southern Ocean sea surface temperatures. This implies a southern middle latitudes-wide millennial rhythm of climate change throughout the last glacial period linked to the north Atlantic by the bipolar seesaw. We suggest that winter insolation, acting alongside other drivers such as the strength and/or position of the southern westerlies, controlled the extents of major southern mountain glaciers such as those in southernmost South America.

Using structure from motion photogrammetry to measure past glacier changes from historic aerial photographs

ABSTRACTQuantifying historic changes in glacier size and mass balance is important for understanding how the cryosphere responds to climate variability and change. Airborne photogrammetry enables glacier extent and equilibrium line altitudes (ELAs) to be monitored for more glaciers at lower cost than traditional mass-balance programs and other remote-sensing techniques. Since 1977, end-of-summer-snowlines, which are a proxy for annual ELAs, have been recorded for 50 glaciers in the Southern Alps of New Zealand using oblique aerial photographs. In this study, we use structure from motion photogrammetry to estimate the camera parameters, including position, for historic photographs, which we then use to measure glacier change. We apply this method to a small maritime New Zealand glacier (Brewster Glacier, 1670–2400 m a.s.l.) to derive annual ELA and length records between 1981 and 2017, and quantify the uncertainties associated with the method. Our length reconstruction shows largely continuous terminus retreat of 365 ± 12 m for Brewster Glacier since 1981. The ELA record, which compares well with glaciological mass-balance data measured between 2005 and 2015, shows pronounced interannual variability. Mean ELAs range from 1707 ± 6 to 2303 ± 5 m a.s.l., with the highest ELAs occurring in the last decade.

Regional cooling caused recent New Zealand glacier advances in a period of global warming

Glaciers experienced worldwide retreat during the twentieth and early twenty first centuries, and the negative trend in global glacier mass balance since the early 1990s is predominantly a response to anthropogenic climate warming. The exceptional terminus advance of some glaciers during recent global warming is thought to relate to locally specific climate conditions, such as increased precipitation. In New Zealand, at least 58 glaciers advanced between 1983 and 2008, and Franz Josef and Fox glaciers advanced nearly continuously during this time. Here we show that the glacier advance phase resulted predominantly from discrete periods of reduced air temperature, rather than increased precipitation. The lower temperatures were associated with anomalous southerly winds and low sea surface temperature in the Tasman Sea region. These conditions result from variability in the structure of the extratropical atmospheric circulation over the South Pacific. While this sequence of climate variability and its effect on New Zealand glaciers is unusual on a global scale, it remains consistent with a climate system that is being modified by humans.

The Southern Glacial Maximum 65,000 years ago and its Unfinished Termination

Glacial maxima and their terminations provide key insights into inter-hemispheric climate dynamics and the coupling of atmosphere, surface and deep ocean, hydrology, and cryosphere, which is fundamental for evaluating the robustness of earth's climate in view of ongoing climate change. The Last Glacial Maximum (LGM, ∼26–19 ka ago) is widely seen as the global cold peak during the last glacial cycle, and its transition to the Holocene interglacial, dubbed 'Termination 1 (T1)', as the most dramatic climate reorganization during this interval. Climate records show that over the last 800 ka, ice ages peaked and terminated on average every 100 ka (‘100 ka world’). However, the mechanisms pacing glacial–interglacial transitions remain controversial and in particular the hemispheric manifestations and underlying orbital to regional driving forces of glacial maxima and subsequent terminations remain poorly understood.Here we show evidence for a full glacial maximum in the Southern Hemisphere 65.1 ± 2.7 ka ago and its ‘Unfinished Termination’. Our 10Be chronology combined with a model simulation demonstrates that New Zealand's glaciers reached their maximum position of the last glacial cycle during Marine Isotope Stage-4 (MIS-4). Southern ocean and greenhouse gas records indicate coeval peak glacial conditions, making the case for the Southern Glacial Maximum about halfway through the last glacial cycle and only 15 ka after the last warm period (MIS-5a). We present the hypothesis that subsequently, driven by boreal summer insolation forcing, a termination began but remained unfinished, possibly because the northern ice sheets were only moderately large and could not supply enough meltwater to the North Atlantic through Heinrich Stadial 6 to drive a full termination. Yet the Unfinished Termination left behind substantial ice on the northern continents (about 50% of the full LGM ice volume) and after another 45 ka of cooling and ice sheet growth the earth was at inter-hemispheric Last Glacial Maximum configuration, when similar orbital forcing hit maximum-size northern ice sheets and ushered in T1 and thus the ongoing interglacial. This argument highlights the critical role of full glacial conditions in both hemispheres for terminations and implies that the Southern Hemisphere climate could transition from interglacial to full glacial conditions in about 15,000 years, while the Northern Hemisphere and its continental ice-sheets required half a glacial cycle.

Annual ice volume changes 1976–2008 for the New Zealand Southern Alps

New Zealand has a long, continuous record of annual end-of-summer-snowline measurements for a set of Southern Alps ‘index glaciers’ from 1977 to present. These index glaciers are used to estimate annual mass balance and volume water equivalent changes for the over 3000 glaciers on the Southern Alps. Two methods are employed to monitor ice volume changes. Method I deals with the rapid to normal response time glaciers, which tend to be small to medium in size. It uses mass balance gradients and glacier areas to convert changes in snowlines to changes in ice volume water equivalent. Ice volume changes for the period 1976–2008 are calculated for each index glacier, and then extrapolated to most other glaciers of the Southern Alps, using the New Zealand glacier inventory. Method II deals with 12 protracted response glaciers, which tend to be large in size. These have been slow in reacting to a long-term regional warming trend. Instead they still largely retain the ablation areas of a century ago and are in a state of disequilibrium with the present climate. These valley glaciers have recently sustained substantial ice losses that are not able to be detected using Method I. Mass balance deficits and ablation from the 12 large protracted response glaciers are estimated using a geodetic approach based on topographic and lake changes determined from repeated surveys. Results show that estimated ice volume (in water equivalents) for the Southern Alps has decreased from 54.5km3 in 1976 to 46.1km3 by 2008. This equates to a rate of −0.3km3a−1 over the last three decades, but this is considerably less than the rate of ice volume loss estimated for the previous 100years. More than 3000 small and medium-size glaciers account for just 29% of the overall ice volume loss from the Southern Alps, while 71% of the loss occurs from the 12 large protracted response glaciers. Terminus calving contributes 0.8km3 and down-wasting of ice tongues in the ablation zone contributes 5.2km3. Some preliminary results show that ice volume changes are related to changes in circulation over the New Zealand region.

Glacier retreat in New Zealand during the Younger Dryas stadial

Millennial-scale cold reversals in the high latitudes of both hemispheres interrupted the last transition from full glacial to interglacial climate conditions. The presence of the Younger Dryas stadial (approximately 12.9 to approximately 11.7 kyr ago) is established throughout much of the Northern Hemisphere, but the global timing, nature and extent of the event are not well established. Evidence in mid to low latitudes of the Southern Hemisphere, in particular, has remained perplexing. The debate has in part focused on the behaviour of mountain glaciers in New Zealand, where previous research has found equivocal evidence for the precise timing of increased or reduced ice extent. The interhemispheric behaviour of the climate system during the Younger Dryas thus remains an open question, fundamentally limiting our ability to formulate realistic models of global climate dynamics for this time period. Here we show that New Zealand's glaciers retreated after approximately 13 kyr bp, at the onset of the Younger Dryas, and in general over the subsequent approximately 1.5-kyr period. Our evidence is based on detailed landform mapping, a high-precision (10)Be chronology and reconstruction of former ice extents and snow lines from well-preserved cirque moraines. Our late-glacial glacier chronology matches climatic trends in Antarctica, Southern Ocean behaviour and variations in atmospheric CO(2). The evidence points to a distinct warming of the southern mid-latitude atmosphere during the Younger Dryas and a close coupling between New Zealand's cryosphere and southern high-latitude climate. These findings support the hypothesis that extensive winter sea ice and curtailed meridional ocean overturning in the North Atlantic led to a strong interhemispheric thermal gradient during late-glacial times, in turn leading to increased upwelling and CO(2) release from the Southern Ocean, thereby triggering Southern Hemisphere warming during the northern Younger Dryas.

Cosmogenic 10Be and 26Al exposure ages of moraines in the Rakaia Valley, New Zealand and the nature of the last termination in New Zealand glacial systems

New Zealand glaciers reached their last glacial maximum position at or before ~ 25 ka, and, as early as 23 ka, commenced a slow and continual retreat. New cosmogenic exposure ages and field mapping from the Rakaia Valley in the South Island suggest that extensive ice survived well into the latter half of the Last Glacial–Interglacial Transition (18–11 ka), with the post-15 ka period inferred to have near Holocene climate conditions based on ecological proxy data. By as late as ~ 15.5 ka, glacier termini had retreated as little as 5–10 km from glacial maximum positions. Numerous minor ice still-stand positions and oscillations are recognized, but the record specifically excludes evidence for either a major climatic amelioration at ~ 15–16 ka or a significant glacial re-advance during the Antarctic Cold Reversal (ACR) or the Younger Dryas (YD). We conclude that the currently widespread interpretation of an episodic New Zealand glacial record since the LGM is an artifact of valley-dependent retreat processes. Pro-glacial lake formation and local site conditions combined to give an apparent, but misleading, picture of glacial retreat punctuated by major, climatically driven, re-advances.

Climate sensitivity of a high-precipitation glacier in New Zealand

AbstractThe sensitivity of glaciers to climatic change is key information in assessing the response and sea-level implications of projected future warming. New Zealand glaciers are important globally as an example of how maritime glaciers will contribute to sea-level rise. A spatially distributed energy-balance model is applied to Brewster Glacier, New Zealand, in order to calculate glacier mass balance, run-off and sensitivity to climate change. The model successfully simulates four annual mass-balance cycles. Close to half (52%) of the energy available for melt on the glacier is supplied by turbulent heat fluxes, with radiation less important, except during the winter. Model sensitivity to temperature change is one of the largest reported on Earth, at −2.0 m w.e. a−1 °C−1. In contrast, a 50% change in precipitation is required to offset the mass-balance change resulting from a 1 °C temperature change. Meltwater runoff sensitivity is also very high, increasing 60% with a 1°C warming. The extreme sensitivity of mass balance to temperature change suggests that significant ice loss will occur with even moderate climate warming.

Teleconnections between Andean and New Zealand glaciers

Retreat and advance of glaciers in the Southern Alps of New Zealand have occurred over two distinct 20-yr climate periods (1954–1974) and (1974–1994). Changes in tropical and southern Andean glaciers are compared over these same periods. Behaviour of glaciers in the tropical Andes are out of phase with the Southern Alps glaciers, but some glaciers in Patagonia appear to be in phase. Southern Hemisphere atmospheric circulation using 700 hPa geopotential height anomalies and sea surface temperature patterns are examined for these periods. Glacier response on inter-decadal timescales is linked with distinctive shifts in atmospheric circulation patterns around the Southern Hemisphere. Retreat (advance) of glaciers in the Southern Alps and southern Andean glacier and advance (retreat) of glaciers in the tropical Andes are all associated with weaker (stronger) westerlies, blocking events in the South-east Pacific, negative (positive) geopotential height anomalies over Southern Africa and higher latitudes of the Southern Hemisphere. These glacier changes are also linked with the negative (positive) phase of the Inter-decadal Pacific Oscillation, a higher frequency of La Niña (El Niño) events, and warm (cool) sea surface temperatures in the New Zealand region and cool (warm) sea surface temperatures in the equatorial eastern region of the Pacific Ocean off the coast of Peru.

Temperature change is the major driver of late-glacial and Holocene glacier fluctuations in New Zealand

Research Article| February 01, 2006 Temperature change is the major driver of late-glacial and Holocene glacier fluctuations in New Zealand Brian Anderson; Brian Anderson 1Antarctic Research Centre and School of Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand Search for other works by this author on: GSW Google Scholar Andrew Mackintosh Andrew Mackintosh 1Antarctic Research Centre and School of Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand Search for other works by this author on: GSW Google Scholar Author and Article Information Brian Anderson 1Antarctic Research Centre and School of Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand Andrew Mackintosh 1Antarctic Research Centre and School of Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand Publisher: Geological Society of America Received: 09 Aug 2005 Revision Received: 20 Oct 2005 Accepted: 22 Oct 2005 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2006) 34 (2): 121–124. https://doi.org/10.1130/G22151.1 Article history Received: 09 Aug 2005 Revision Received: 20 Oct 2005 Accepted: 22 Oct 2005 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Brian Anderson, Andrew Mackintosh; Temperature change is the major driver of late-glacial and Holocene glacier fluctuations in New Zealand. Geology 2006;; 34 (2): 121–124. doi: https://doi.org/10.1130/G22151.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Advance and retreat of temperate glaciers is largely controlled by changes in temperature and precipitation, but the relative importance of these drivers is debated. Numerical modeling of a New Zealand glacier reveals that temperature is the dominant control on glacier length. We find that a glacial advance, dated to ca. 13,000 yr B.P., requires a cooling event of 3–4 °C. This mid-latitude Southern Hemisphere cooling is similar in magnitude to the Antarctic Cold Reversal in the Vostok ice core record and likely to be a response to the same climate signal. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Estimates of Australian dust flux into New Zealand: Quantifying the eastern Australian dust plume pathway using trace element calibrated 210Pb as a monitor

Abstract Weekly average atmospheric 210 Pb flux data collected between March 1989 and February 2001 are used to construct a record of Australian dust incursions onto the west coast, South Island, New Zealand. Dusts collected from New Zealand glaciers were found to contain a mixture of local New Zealand and long range Australian material, based on novel binary and tertiary mixing models of their ultra trace element chemistries. Trace element characteristics further allowed determination of the provenance of the long range dust component within Australia to better than 200 km resolution. 210 Pb analyses of these chemically characterised dust samples show that activity is related to the percentage of Australian dust in a linear fashion. However, 210 Pb activity of Australian dusts collected in New Zealand is orders of magnitude greater than that measured in the alluvial sediments of the provenance areas. Australian dusts collected in New Zealand are also highly enriched in 210 Pb compared to dusts collected in Australia. This shows that dust scavenges atmospheric 210 Pb which can therefore be used as an effective tracer of long range dust transport. Previously obtained average atmospheric 210 Pb flux data can thus be converted into the first record of long range Australian dust flux in New Zealand. Results show that the average atmospheric concentration of Australian dust in New Zealand is 5.3 μg m − 3 . There is a clear seasonality with the highest concentrations occurring in autumn–winter, preceding Australia's major dust storm season, which occurs in winter–spring. We propose that while meteorological factors control the occurrence of major dust storms, the availability of sediment in source areas is a major control on Australian dust flux in New Zealand. Dust flux is greatest after seasonal river flows when transport of extremely fine grained dust occurs. This is followed by transport of larger particles in the more spectacular winter–spring dust storms. Our results provide information on the characteristics and seasonality of dust transport in the Australian region, which had previously been difficult to quantify by other methods (e.g., satellite imagery). Results also attest to the effectiveness of 210 Pb as a tracer in this region.

Provenance of long‐travelled dust determined with ultra‐trace‐element composition: a pilot study with samples from New Zealand glaciers

AbstractWe report high‐precision inductively coupled plasma mass spectrometric (ICP‐MS) compositional data for 39 trace elements in a variety of dust deposits, trapped sediments and surface samples from New Zealand and Australia. Dusts collected from the surface of alpine glaciers in the Southern Alps, New Zealand, believed to have undergone long‐distance atmospheric transport from Australia, are recognizable on account of their overabundances of Pb and Cu with respect to typical upper crustal values. Long‐travelled dust from Australia therefore scavenges these and other metals (e.g. Zn, Sb and Cd) from the atmosphere during transport and deposition. Hence, due to anthropogenic pollution, long‐travelled Australian dusts can be recognized by elevated metal contents.The relative abundance of 25 other elements that are not affected by atmospheric pollution, mineral sorting (Zr and Hf) and weathering[sol ]solubility (alkali and earth alkali elements) reflects the geochemistry of the dust source sediment. As a result, we are able to establish the provenance of dust using ultra‐trace‐element chemistry at regional scale. Comparison of long‐travelled dust chemistry with potential Australian sources shows that fits of variable quality are obtained. We propose that the best fitting potential source chemistry most likely represents the major dust source area. A binary mixing model is used to demonstrate that admixture of small quantities of local dust provides an even better fitting dust chemistry for the long‐travelled dusts. Copyright © 2005 John Wiley & Sons, Ltd.

Climatic control of riverine and seawater uranium-isotope ratios.

The large variation in the ratio of uranium-234 to uranium-238 (234U/238U) in rivers is not well understood, but may provide information about past weathering and rainfall and is important because it controls seawater (234U/238U). Here, we demonstrate the importance of physical weathering and rainfall for (234U/238U), using rivers from South Island, New Zealand. These data allow interpretation of an existing speleothem (234U/238U) record and suggest that New Zealand glacier advance 13,000 years ago was influenced by increased rainfall rather than by Younger Dryas-like cooling. A model of seawater (234U/238U) during glacial cycles indicates that rejection of corals based on modern (234U/238U) +/- <0.01 is not merited and may reject the highest quality ages.

Onset of Neoglaciation in the Southern Hemisphere

A review of evidence documenting an early Neoglacial (mid-Holocene) advance of mountain glaciers in South America and New Zealand reveals that of 16 glaciers for which radiocarbon age control exists, only two have associated dates that may approximate the culmination of an advance. Advances of the remaining glaciers are controlled only by minimum or maximum limiting ages. Additional dates for several New Zealand glaciers are based on weathering-rind measurements having large potential errors. Twelve of the glaciers now terminate or have terminated in lakes or in tidewater and are subject to instabilities associated with calving termini. An extensive debris cover in the ablation zone of nearly half of the glaciers makes their moraine succession potentially suspect as a record of detailed climatic variation. The two glaciers with seemingly reliable age control are located in valleys where large rock avalanches could affect glacier mass balance and lead to random advances, or where rock avalanche deposits might easily be mistaken for moraines and tills. The early Neoglacial interval has been defined primarily based on this set of data. The ages, taken at face value, suggest that the early Neoglacial advance culminated between ca. 5400 and 4900 cal yr ago (ca. 4600–4400 14C yr BP). This chronology, however, should remain provisional until improved age control is obtained for a large population of glaciers based on closely bracketing radiocarbon dates and/or an adequate number of cosmogenic isotope ages. Data from calving glaciers and those subject to rock-avalanche activity should be avoided or assessed critically. Copyright © 2000 John Wiley & Sons, Ltd.

Research on glaciers and snow in New Zealand

The glaciers and snowfields of the Southern Alps of New Zealand are the most significant in the Southern Hemisphere outside Antarctica and South America. The most substantial data on Southern Hemisphere glacier fluctuations come from New Zealand. The nature and behaviour of New Zealand's glaciers are also of wider scientific interest, because they are highly sensitive, high input-output systems that represent the temperate, maritime end of the glacier process-behaviour continuum. The areal extent and volume of glaciers and snow are outlined and an assessment is made of their scientific relevance and of their importance as resources and hazards. The main themes and progress of research on glaciers and snow, including snow avalanches, are reviewed. Glacier research has concentrated on only a few key glaciers and has focused on understanding glacier change. Main topics covered in this review relate to this focus and include fluctuations in termini, other mass balance signals and response to climate variability. Research on mass balance processes, glacier dynamics and glacier hydrology is also outlined. Seasonal snow has received less attention until recently. The main emphasis has been on quantification and past variability and its contribution to river flow, particularly in the most important hydroelectric power catchments of the South Island. Some field measurements have been made of the energy balance over snow. Research on snow avalanches has grown as the demands of winter recreation and alpine tourism have increased the hazard. Research first concentrated on production of avalanche atlases for the most hazardous areas and on quantifying the nature of the hazard. Subsequently, there has been a shift towards more process studies that are related to avalanche formation and runout distance. The main gaps in research on glaciers and snow are identified and key areas for future work proposed. There is an urgent need, in particular, for glacier mass-balance measurements. Extensive data on snow structure need to be synthesized. Satellite imagery should be used for monitoring of seasonal snow. Snow melt during northwest storms needs to be better defined. A more developed engineering approach is required for the study of snow avalanches. New Zealand offers exciting possibilities for the study of cryospheric processes, including response to future climate change.