The importance of the geophysical context in statistical evaluations of climate reconstruction procedures

A portion of the debate about climate reconstructions of the past millennium, and in particular about the well-known Mann-Bradley-Hughes (“MBH” 1998, 1999) reconstructions, has become disconnected from the goal of understanding natural climate variability. Here, we reflect on what can be learned from recent scientific exchanges and identify important challenges that remain to be addressed openly and productively by the community. One challenge arises from the real, underlying trend in temperatures during the instrumental period. This trend can affect regression-based reconstruction performance in cases where the calibration period does not appropriately cover the range of conditions encountered during the reconstruction. However, because it is tied to a unique spatial pattern driven by change in radiative balance, the trend cannot simply be removed in the method of climate field reconstruction used by MBH on the statistical argument of preserving degrees of freedom. More appropriately, the influence from the trend can be taken into account in some methods of significance testing. We illustrate these considerations as they apply to the MBH reconstruction and show that it remains robust back to AD 1450, and given other empirical information also back to AD 1000. However, there is now a need to move beyond hemispheric average temperatures and to focus instead on resolving climate variability at the socially more relevant regional scale.     

The Water-Bearing Numerical Model and Its Operational Forecasting Experiments PartII: The Operational Forecasting Experiments

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The Australian Air Quality Forecasting System: Exploring First Steps Towards Determining The Limits of Predictability For Short-Term Ozone Forecasting

Physical parameterisations of turbulent transfer processes in the atmospheric boundary layer, such as the stability parameterisations developed by Joost Businger, and recent advances in computing capabilities, have been important factors leading to the emergence of operational, numerical air quality forecasting systems. The present paper investigates the performance of the Australian Air Quality Forecasting System (AAQFS) in forecasting the peak 1 h ozone for the current or next day. These 24/36 h forecasts are generated for the Sydney and Melbourne regions and issued twice daily. Quantitative evidence is presented of the potential for the AAQFS to provide accurate numerical air quality forecasts. A second goal is to provide an initial benchmark for investigating the limits of predictability for air quality in the Sydney and Melbourne regions by looking at the dependence of the forecasts on the domain spatial scale (while maintaining the same model grid resolution), the starting time and length of the forecast (0000 UTC starts are 36-h forecasts and 1200 UTC starts are 24-h forecasts), and the sophistication of the photochemical mechanism (simple chemistry, Generic Reaction Set (GRS) and complex chemistry, Carbon Bond IV (CBIV)). The probability of detection by the forecast model is much better than persistence, showing considerable skill. The normalised bias, in general, decreases going from regional scale to sub-regional scale and becomes negative at the station scale. In Melbourne the gross error increases as the domain spatial scale decreases, but in Sydney there is a dip in the error at the sub-regional scale due to a sampling artifact. Better results are obtained at the smaller domain scales for 1200 UTC forecasts in Sydney. These are attributed to the shorter forecast period and secondarily to greater model spin-up effects at 0000 UTC. In Melbourne the results are ambiguous. Similar conclusions are derived from scatter plots of forecasts versus observations. Dividing the scatter plots into four sections by plotting vertical and horizontal lines (at 60 ppb) forms contingency tables for categorical forecasting. These plots show the increase in missed forecasts due to underprediction and the decrease in the number of extreme events detected as the spatial scale decreases. A comparison of the highly condensed GRS photochemical mechanism with the comprehensive CBIV mechanism indicates that, in general, GRS performs well for predicting ozone in urban situations provided that the background concentrations are appropriately specified. The potential to improve the forecasts at the smaller spatial scales, particularly for extreme events at high ozone concentrations, may require moving to a more complex mechanism as computer resources become available. This paper is dedicated to Joost Businger, who had strong ties with the atmospheric boundary-layer community in Australia over the past 40 years. It was while visiting CSIRO in Aspendale, Victoria, in 1965–1966 that Joost determined the stability dependence of the Monin-Obukhov surface-layer profiles. He immediately walked over to Arch Dyer’s office to show Arch his results. Arch carefully examined them, and then opened his desk drawer and pulled out his own plots of the stability dependence that he and Bruce Hicks had obtained. They showed the same curves, and thus the Businger-Dyer-Hicks stability functions were born. Arch and Bruce at the time were struggling with how to handle the internal politics; they needed Bill Swinbank’s approval, as Assistant Divisional Chief, before they could submit their results for publication. Bill had his own very strong ideas that conflicted with observations. Joost’s independent confirmation of their results provided a way forward (Bruce Hicks, personal communication, 2003). Joost has contributed significantly, either directly or indirectly, to experimental field programs both within Australia and overseas and to the development of parameterisations of turbulent transfer processes in the boundary layer.     

The complex decision-making of climate-induced relocation: adaptation and loss and damage

Climate change is increasingly challenging the ability of millions of people to sustain livelihoods as the places where they live become uninhabitable. The relocation of populations as individuals, households, and communities within countries and across international borders demonstrates the complexity of climate change impacts. Looking at the literature, some researchers argue that relocation caused by climate change can be an effective strategy to adapt to localized changes, whereas others argue that the movement away from ones' homeland is more neatly captured in the climate change lexicon as ‘loss and damage’. We argue here that the relocation of people as a result of the impacts of climate change can be both adaptation and loss and damage. Drawing on examples from Alaska and Kiribati, we show that dividing this issue between the two concepts is unhelpful in resolving key issues around the types of appropriate support for these transitions to sustain and protect livelihoods and to open up possibilities for self-determined futures.

Policy Relevance

Climate-induced relocation poses a significant challenge for the populations affected as well as the government agencies tasked with providing technical assistance and funding. At present, policies and institutional frameworks have not yet been developed to accommodate these challenges, despite the urgent need to do so. When the relocation of populations can be planned, participatory, and people centred, then it can be an adaptation strategy that will protect people from the permanent loss of land and livelihoods. If these movements are decided, driven, managed, and undertaken by those affected, then there is the potential for the relocation to also be a transformative opportunity for people to respond to the impacts of climate change, and sustain their livelihoods and possibly even improve certain livelihood outcomes. However, these relocations also cause significant loss and damage. The extent of the loss and damage will partly depend on the ability to have these relocations planned and ensure that human rights protections are embedded in institutional frameworks. The article shares a series of lessons and learnings that are of policy relevance at a variety of scales.     

基于相似离度的相似预报系统

相似高度法是短期气候预测中常用的预报方法之一，该方法能够同时考虑环流场之间在形态和数值两方面的相似情况，是一种比较全面客观的相似衡量标准。依据相似离度的原理，利用可视化编程工具Visual Basic 6.0，开发了分析500hPa高度场相似离度并结合本地资料进行降水量预报的业务系统。     

松花江流凌预报方法

为了充分开发、利用水利资源，在分析大气环流与流凌关系的基础上，采用统计方法，对松花江流凌进行了气候分析，确定了流凌与气象因子的关系，为航运局航道局提供航运决策，收到了明显的经济效益和社会效益。     

基于相似离度的相似预报系统

相似离度法是短期气候预测中常用的预报方法之一,该方法能够同时考虑环流场之间在形态和数值两方面的相似情况,是一种比较全面客观的相似衡量标准.依据相似离度的原理,利用可视化编程工具Visual Basic6.0,开发了分析500 hPa高度场相似离度并结合本地资料进行降水量预报的业务系统.     

载水数值模式的实时预报试验

该文对载水数值模式进行了持续56天的实时预报试验,并对模式的常规预报和云场预报结果进行检验和分析。试验表明,模式运行稳定可靠;载水数值模式有能力合理而比较正确地预报大气中各种水物质的分布及随时间变化,预报云系、云团的宏、微观结构和云物理特征;与此同时,其形势预报及以降水为代表的要素预报能力,亦不低于一般的常规预报模式。     

武威地区中期天气预报系统

利用ＥＣＭＷＦ数值预报产品和ＰＰ法律建立指标模型,把天气动力、定量统计、相似分析运用到中期天气预报中,并做了有益的尝试。     

月平均气温集成预测方法研究

为了有效综合各种预测方法的预测结果,以陕西3个气候区域1999年7月至2010年6月月平均气温的集成预测为例,利用3种预测方法和国家气候中心业务产品月平均气温预测结果历史评分建立二类6种动态客观集成预测方法进行对比研究,结果表明：（1）各种集成预测方法年评分平均值均高于参加集成的任何一个成员,6种集成预测方法评分平均值比4个成员评分平均值高4.6,比同期陕西发布的业务产品高5.1;各种集成预测方法预测与实况距平符号一致率至少高于其中3个成员,6种集成预测方法预测与实况距平符号一致率平均值比4个成员平均值高4.7%,比陕西业务产品高5.1%。（2）3个气候区域中,榆林集成预测效果最好。6种集成预测方法评分平均值比4个成员评分平均值高5.7,比陕西业务产品高5.7;预测与实况距平符号一致率比4个成员高6.9%,比陕西业务产品高7.3%。（3）第二类集成预测方法预测技巧高于第一类,全年评分平均值高0.5,预测与实况距平符号一致率高0.7%。其中Z_（23）全年评分平均值比4个成员评分平均值高5.1,比陕西业务产品高5.7,预测与实况距平符号一致率比4个成员高6.0%,比陕西业务产品高7.6%,推荐首先选择使用。     

The importance of precessional signals in the tropical climate

Past research on the climate response to orbital forcing has emphasized the glacial-interglacial variations in global ice volume, global-mean temperature, and the global hydrologic cycle. This emphasis may be inappropriate in the tropics, where the response to precessional forcing is likely to be somewhat independent of the glacial-interglacial variations, particularly in variables relating to the hydrologic cycle. To illustrate this point, we use an atmospheric general circulation model coupled to a slab ocean model, performing experiments that quantify the tropical climates response to (1) opposite phases of precessional forcing, and (2) Last Glacial Maximum boundary conditions. While the glacially-forced tropical temperature changes are typically more than an order of magnitude larger than those arising from precessional forcing, the hydrologic signals stemming from the two forcings are comparable in magnitude. The mechanisms behind these signals are investigated and shown to be quite distinct for the precessional and glacial forcing. Because of strong dynamical linkages in the tropics, the model results illustrate the impossibility of predicting the local hydrologic response to external forcing without understanding the response at much larger spatial scales. Examples from the paleoclimate record are presented as additional evidence for the importance of precessional signals in past variations of the tropical climate.     

中国"代"尺度气候预测

将子波分析技术与随机动力学相结合,提出了突变点数建模代尺度气候预测新技术—突变点数建模技术,并将该技术应用于中国不同地区代尺度的干湿驰豫时间的预报。研究结果表明,在代尺度上,我国北方、西南和东南气候灾害频繁,南方多涝,西北和北方(不包括东北)则多旱。由于该技术是关于时间序列建模的,故可以应用到水文、地震、生态等领域有关的建模和预测。     

Evaluation of the CORDEX-Africa multi-RCM hindcast: systematic model errors

Monthly-mean precipitation, mean (T_AVG), maximum (T_MAX) and minimum (T_MIN) surface air temperatures, and cloudiness from the CORDEX-Africa regional climate model (RCM) hindcast experiment are evaluated for model skill and systematic biases. All RCMs simulate basic climatological features of these variables reasonably, but systematic biases also occur across these models. All RCMs show higher fidelity in simulating precipitation for the west part of Africa than for the east part, and for the tropics than for northern Sahara. Interannual variation in the wet season rainfall is better simulated for the western Sahel than for the Ethiopian Highlands. RCM skill is higher for T_AVG and T_MAX than for T_MIN, and regionally, for the subtropics than for the tropics. RCM skill in simulating cloudiness is generally lower than for precipitation or temperatures. For all variables, multi-model ensemble (ENS) generally outperforms individual models included in ENS. An overarching conclusion in this study is that some model biases vary systematically for regions, variables, and metrics, posing difficulties in defining a single representative index to measure model fidelity, especially for constructing ENS. This is an important concern in climate change impact assessment studies because most assessment models are run for specific regions/sectors with forcing data derived from model outputs. Thus, model evaluation and ENS construction must be performed separately for regions, variables, and metrics as required by specific analysis and/or assessments. Evaluations using multiple reference datasets reveal that cross-examination, quality control, and uncertainty estimates of reference data are crucial in model evaluations.     

Heat health planning: The importance of social and community factors

Extreme heat events frequently have adverse effects on population health. Within every population certain groups and individuals are at a greater risk of heat-related morbidity and mortality than others. While certain physiological characteristics (advanced age, chronic conditions, etc.) are known to increase the risk of illness and/or death during periods of extreme heat, the role of social and community level factors in aggravating or mitigating this risk is poorly understood. This paper reviews the literature on the social and community level factors that affect heat-related morbidity and mortality in order to identify shortfalls in current heat health response plans so that new approaches can be recommended. While social isolation, ethnicity, socioeconomic status, and neighborhood characteristics have all been identified as potential factors affecting the risk of heat-related illness and mortality, these are rarely, if ever, identified as heat health research priorities and are thus often neglected in heat emergency planning. Current research and programming practices are often prioritized from the top down where decisions are made at the federal level and research priorities are determined by national research bodies. This, unfortunately, may not allow enough flexibility to meet the needs of physically, socially and culturally diverse communities. A more socio-ecological approach to heat health research and planning would better allow for the identification of community level vulnerabilities and available resources and would encourage communities to work with regional or national partners to adapt response plans accordingly. The development of future plans should involve more partnerships at the community level so that social and community level factors that are currently overlooked may be included in heat health response strategies.     

The influence of systematic errors on the asian summer monsoon circulation

1. IntroductionThe Asian summer monsoon circulation is a thermally driven circulation, which arisesprimarily from the temperature differences between the warmer continental areas of theNorthern Hemisphere and the oceans of the Southern Hemisphere. The complex feedback between the flow field and the heating, especially through the interaction between thelarge--scale flow and moist convection, is yet to be well understood. Nevertheless, this facetensures the prominence of the summer monsoon ci…     

新一代省级农业气象预报系统通用统计预报模型的设计与实现

统计预报方法是农业气象预报业务中常用的一种方法.在"新一代农业气象预报系统"中,系统设计了一种通用统计预报模型构建方法,可用于作物产量预报、农业气象灾害预报等农气预报业务.本文主要介绍了通用预报模型的设计原理、实现方法及应用试验结果等.     

新一代省级农业气象预报系统通用统计预报模型的设计与实现

统计预报方法是农业气象预报业务中常用的一种方法。在“新一代农业气象预报系统”中，系统设计了一种通用统计预报模型构建方法，可用于作物产量预报、农业气象灾害预报等农气预报业务。本文主要介绍了通用预报模型的设计原理、实现方法及应用试验结果等。     

温度客观预报自动化业务系统

介绍了一以Ｔ６３数值预报产品为因子，用卡尔曼滤波方法作４８小时最高，最低温度客观预报方法及其自动化业务系统，能补充目前地市台温度预报主要依靠主观预报的不足，对温度有一定的预报能力。     

The Use of Seasonal Climate Forecasting in Policymaking: Lessons from Northeast Brazil

This article examines the use of seasonal climate forecasting in public and private efforts to mitigate the impacts of drought in Ceará, Northeast Brazil. Here, forecasts have been directed towards small scale, rainfed agriculturalists as well as state and local level policymakers in the areas of agriculture, water management, and emergency drought relief. In assessing possibilities and constraints of forecast application in Ceará, the present analysis takes into account three types of variables: (a)characteristics of the forecasts; (b) policymaking systems; and (c)institutional environments. We conclude that, on the one hand, several factors in the Ceará case have limited the effectiveness of seasonal climate forecast use. First, the current level of skill of the forecasts is inadequate for the needs of policy development and farmer decisionmaking. Second, forecast information application has been subject to distortion, misinterpretation and political manipulation. Third, focus on the forecast as a product until recently neglected to take into account end users' needs and decisionmaking behavior. On the other hand, climate forecasting has the potential to offer a dramatic opportunity for state and local level bureaucracies to embark on a path of proactive drought planning.     

三门峡市短时暴雨预报方法

通过对三门峡市1997～2001年6～8月雷达资料及地面、高空气象资料统计分析,挑选出4个与短时暴雨相关性较好的预报因子,利用概率回归方法,建立了短时暴雨预报方程.