Partnering between a geography department and a community initiative to provide a wind resource assessment for the Blueskin Bay region,Otago, New Zealand

This paper explores the partnership between a community group and a geography department to assess the wind energy potential of the Blueskin Bay region in southern New Zealand. The partnership has provided opportunities for research and is of strategic importance. Year‐long wind observations and numerical modelling have revealed that the hills surrounding Blueskin Bay show potential for wind energy generation. Despite challenges for both parties, the university–community partnership has allowed a successful research platform to be established.     

Freshwater geographies: Experimenting with knowing and doing geography differently

The fair and effective governance of freshwater is an increasingly prominent issue in New Zealand. Emerging from a complex of cultural, economic and biophysical narratives, freshwater geographies are multiple, varied and increasingly acknowledged as worthy of interdisciplinary scrutiny. In this commentary, we reflect on a series of generative spaces that we – as group of postgraduate geographers (plus supporting staff) – created to engage with the multiplicity of freshwater meanings both within and beyond the academy. Through this evolving epistemic‐political project, we significantly reframed our own understandings about what freshwater ‘is’ and how it ought to be governed. By pursuing a deeper understanding of how the world gets made, we expand our ability to know and make it differently.     

Analysis of the Devonian (Frasnian) platform from Belgium: a multi‐faceted approach for basin evolution reconstruction

This study undertakes a multi‐disciplinary approach (sedimentology, carbon isotopes, magnetic susceptibility and thickness distribution) to improve understanding of a major Palaeozoic carbonate platform, the Frasnian platform of Belgium. These combined techniques are used to reconstruct the platform history, which evolved in two main steps. During the first phase, the basin was strongly influenced by faulting, producing notable thickness and facies variations, with open ocean conditions, with good water circulation and no/or limited barrier reef. The second phase of platform development was less influenced by differential subsidence, as indicated by homogeneous facies distribution. However, this platform developed under restricted waters, with low circulation which is likely related to the development of a barrier reef.     

A Large-Eddy Simulation Study of Water Vapour and Carbon Dioxide Isotopes in the Atmospheric Boundary Layer

A large-eddy simulation model developed at the National Center for Atmospheric Research (NCAR) is extended to simulate the transport and diffusion of C¹⁸OO, H₂¹⁸O and ¹³CO₂ in the atmospheric boundary layer (ABL). The simulation results show that the ¹⁸O compositions of leaf water and the ABL CO₂ are moderately sensitive to wind speed. The variations in the ¹⁸O composition of water vapour are an order of magnitude greater than those in the ¹³C and ¹⁸O compositions of CO₂ both at turbulent eddy scales and across the capping inversion. In a fully-developed convective ABL, these isotopic compositions are well mixed as with other conserved atmospheric quantities. The Keeling intercepts determined with the simulated high-frequency turbulence time series do not give a reliable estimate of the ¹⁸O composition of the surface water vapour flux and may be a reasonable approximation to the ¹³C and ¹⁸O compositions of the surface CO₂ flux in the late afternoon only after a deep convective ABL has developed. We suggest that our isotopic large-eddy simulation (ISOLES) model should be a useful tool for testing and formulating research hypotheses on land–air isotopic exchanges.     

Assessment of the changes in extreme vulnerability over East Asia due to global warming

A number of indices have been employed to describe weather extremes on the basis of climate regimes and public concerns. In this study, we combined these traditional indices into four groups according to whether they relate to warm (T_warm), cold (T_cold), wet (P_wet), or dry (P_dry) extremes. Analysis of the combined indices calculated for the daily temperatures and precipitation at 750 meteorological stations in Korea, China, and Japan for 1960s?C2000s shows increasing trends in T_warm and P_dry events and decreasing trends in T_cold events in recent decades, particularly in the northern part of East Asia. A notable regional variation is an increase in the P_wet events in the Korean Peninsula. We applied the same analysis to a 200-year global climate model simulation for 1900?C2099 using the National Center for Atmospheric Research-Community Climate System Model 3. During the 20th century, the changes in T_warm and T_cold calculated from the model data are largely consistent with those calculated from the observations, especially in northern East Asia. The model projections for the 21st century indicate statistically significant increasing T_warm and decreasing T_cold trends in extreme events over the region. Results obtained from historical archives and model simulations using our combined weather extreme indices suggest that northern East Asia will be subject to increased warm and dry extremes and the Korea Peninsula will experience more wet extremes.     

The influences of interannual stratification variability and wind stress forcing on ENSO before and after the 1976 climate shift

In order to understand the change in oceanic variability associated with the climate shift of the mid-1970s, we analyze the contribution of momentum forcing to the leading baroclinic modes over the tropical Pacific using Simple Ocean Data Assimilation (SODA, version 2.0.2) for the period of 1958–1997. Specifically, we look at the statistical relationship between the wind projection coefficients and climate indices and attempt to provide a physical explanation for the observed changes. It is found that the wind stress projection coefficients according to the oceanic baroclinic modes are different in terms of their magnitude and phase in the tropical Pacific, reflecting a specific forcing associated with each mode before and after the 1976 climate shift. Compared to that before the 1970s, the first baroclinic mode is had a greater effect on the interannual sea surface temperature due to equatorial wave dynamics, and there was an increased delayed response of the second baroclinic mode variability to the interannual atmospheric forcing after the late 1970s. This reflects changes in ENSO feedback processes associated with the climate shift. Our analysis further indicates that, after the late 1970s, there was a decrease in the wind stress forcing projecting onto the Ekman layer, which is associated with increased mixed-layer depth. This result suggests that the changes in the ENSO properties before and after the late 1970s are largely associated with the changes in the way in which the wind stress forcing is dynamically projected onto the surface layer of the tropical Pacific Ocean over interannual timescales.     

Effects of high-resolution land cover and topography on local circulations in two different coastal regions of Korea: a numerical modeling study

The effects of high-resolution land cover (LC) and topography (TP) on coastal wind circulations were evaluated in two different coastal regions of Korea (i.e. a southwestern coast (SWC), including a fairly complex coastline and a number of islands, and an eastern coast (EC), including a simple coastline with high mountains) during spring 2007. These analyses were performed based on a numerical modeling approach, using data sets with different resolutions, such as the LC and TP from the U.S. Geological Survey (USGS-LC and USGS-TP: a 900-m resolution), the LC from the Environmental Geographic Information System (EGIS-LC: a 90-m), and the TP from the Shuttle Radar Topography Mission (SRTM-TP: a 90-m). The combined effects of the LC and TP on the spatial distributions of the coastal winds in the SWC region during the day were somewhat higher than those of the EC region, mainly due to the daytime land surface warming or the extension of the coastal area resulting from changes in the LC. At night, the effects of the EC region were more apparent along the coastline and adjacent sea. From the correlation analyses, the effect of the LC on the vertical wind distributions on land during the day was higher in the SWC region than in the EC region and vice versa for the effect of the TP. In particular, large effects of the LC and TP occurred in the EC region at night and at sea due to the differences in the surface conditions and elevations resulting from the changes in the LC and TP, respectively. In addition, the circulation of coastal winds from the near surface to the upper levels occurred at a relatively high elevation in the EC region (about 1,500?m) relative to the SWC region (about 600?m).     

Advance and prospectus of seasonal prediction: assessment of the APCC/CliPAS 14-model ensemble retrospective seasonal prediction (1980–2004)

We assessed current status of multi-model ensemble (MME) deterministic and probabilistic seasonal prediction based on 25-year (1980–2004) retrospective forecasts performed by 14 climate model systems (7 one-tier and 7 two-tier systems) that participate in the Climate Prediction and its Application to Society (CliPAS) project sponsored by the Asian-Pacific Economic Cooperation Climate Center (APCC). We also evaluated seven DEMETER models’ MME for the period of 1981–2001 for comparison. Based on the assessment, future direction for improvement of seasonal prediction is discussed. We found that two measures of probabilistic forecast skill, the Brier Skill Score (BSS) and Area under the Relative Operating Characteristic curve (AROC), display similar spatial patterns as those represented by temporal correlation coefficient (TCC) score of deterministic MME forecast. A TCC score of 0.6 corresponds approximately to a BSS of 0.1 and an AROC of 0.7 and beyond these critical threshold values, they are almost linearly correlated. The MME method is demonstrated to be a valuable approach for reducing errors and quantifying forecast uncertainty due to model formulation. The MME prediction skill is substantially better than the averaged skill of all individual models. For instance, the TCC score of CliPAS one-tier MME forecast of Niño 3.4 index at a 6-month lead initiated from 1 May is 0.77, which is significantly higher than the corresponding averaged skill of seven individual coupled models (0.63). The MME made by using 14 coupled models from both DEMETER and CliPAS shows an even higher TCC score of 0.87. Effectiveness of MME depends on the averaged skill of individual models and their mutual independency. For probabilistic forecast the CliPAS MME gains considerable skill from increased forecast reliability as the number of model being used increases; the forecast resolution also increases for 2 m temperature but slightly decreases for precipitation. Equatorial Sea Surface Temperature (SST) anomalies are primary sources of atmospheric climate variability worldwide. The MME 1-month lead hindcast can predict, with high fidelity, the spatial–temporal structures of the first two leading empirical orthogonal modes of the equatorial SST anomalies for both boreal summer (JJA) and winter (DJF), which account for about 80–90% of the total variance. The major bias is a westward shift of SST anomaly between the dateline and 120°E, which may potentially degrade global teleconnection associated with it. The TCC score for SST predictions over the equatorial eastern Indian Ocean reaches about 0.68 with a 6-month lead forecast. However, the TCC score for Indian Ocean Dipole (IOD) index drops below 0.40 at a 3-month lead for both the May and November initial conditions due to the prediction barriers across July, and January, respectively. The MME prediction skills are well correlated with the amplitude of Niño 3.4 SST variation. The forecasts for 2 m air temperature are better in El Niño years than in La Niña years. The precipitation and circulation are predicted better in ENSO-decaying JJA than in ENSO-developing JJA. There is virtually no skill in ENSO-neutral years. Continuing improvement of the one-tier climate model’s slow coupled dynamics in reproducing realistic amplitude, spatial patterns, and temporal evolution of ENSO cycle is a key for long-lead seasonal forecast. Forecast of monsoon precipitation remains a major challenge. The seasonal rainfall predictions over land and during local summer have little skill, especially over tropical Africa. The differences in forecast skills over land areas between the CliPAS and DEMETER MMEs indicate potentials for further improvement of prediction over land. There is an urgent need to assess impacts of land surface initialization on the skill of seasonal and monthly forecast using a multi-model framework.     

两种初始场MM5模式预报效果对比评估

为了解本地MM5模式的预报性能,根据其预报结果,检验了基于NCEP和T213两种初始场MM5模式在河北以及京津地区2007年8月至2008年1月的降水、日极值温度和相对湿度的预报效果。结果表明,MM5晴雨（雪）预报的准确率较高,具有较好的参考价值,而对于降水的分级预报,随着预报时效的延长和降水强度的增加,其可用性逐渐降低,但整体来看基于NCEP初始场的预报均比T213初始场预报效果明显;在日极值温度预报中,最低温度效果优于最高温度,T213初始场的预报对日最高温度预报的准确率较高,NCEP初始场的预报则在日最低温度预报中略胜一筹;对08：00相对湿度的预报,两者的预报效果基本相同,绝对误差都在15％左右。     

清洁发展机制（CDM）造林再造林项目碳汇成本研究——以CDM广西珠江流域治理再造林项目为例

以清洁发展机制（CDM）广西珠江流域治理再造林项目为例,对项目及其5种造林模式临时核证减排量（temporary certified emission reduction,缩写为tCER）和长期核证减排量（long-term certified emission reduction,缩写为lCER）成本的动态变化进行了初步研究。结果表明：从项目期初到期末,整个项目及5种造林模式人工林的tCER成本均逐渐降低,其中项目成本由第一承诺期末的40.33 ￥/t CO₂降至最后承诺期末的13.34 ￥/t CO₂;lCER成本先降低后升高,在第一承诺期末均降至最小值,项目成本由第一承诺期末的40.33 ￥/t CO₂增加至最后承诺期末的105.27 ￥/t CO₂;各造林模式tCER和lCER成本均以枫香+杉木、枫香+马尾松较高,马尾松+荷木、马尾松+栎类较低,桉树最低;贴现率对项目tCER和lCER、桉树tCER、枫香+杉木lCER成本影响均较大,而对马尾松+栎类tCER和lCER成本影响均较小;对桉树一个轮伐期内的tCER成本进行了敏感性分析,单位面积碳贮量的变化对其影响较大;考虑木材收益时,项目期末tCER净现值为13.11 ￥/t CO₂,从中反映了该CDM项目实施是可行的。