Sharp depletion of atmospheric refractive index associated with Nor��wester over Gangetic West Bengal: a possible method of forecasting Nor��wester

The paper presents the nature of the variation of refractive index of atmospheric medium with time and altitude before, during and after the onset of thunderstorms over Gangetic West Bengal during the pre-monsoon period. A critical analysis shows that sharp depletion of the refractive index takes place before the onset of Nor??westers and possible explanations are also offered for the said occurrence.     

Is it possible to limit global warming to no more than 1.5°C?

This study explores the feasibility of limiting increases in global temperature to 1.5°C above pre-industrial levels. A probabilistic simple climate model is used to identify emissions paths that offer at least a 50% chance of achieving this goal. We conclude that it is more likely than not that warming would exceed 1.5°C, at least temporarily, under plausible mitigation scenarios. We have identified three criteria of emissions paths that could meet the 1.5°C goal with a temporary overshoot of no more than 50 years: early and strong reductions in emissions, with global emissions peaking in 2015 and falling to at most 44–48 GtCO₂e in 2020; rapid reductions in annual global emissions after 2020 (of at least 3–4% per year); very low annual global emissions by 2100 (less than 2–4 GtCO₂e) and falling to zero (or below) in the 22nd century. The feasibility of these characteristics is uncertain. We conclude that the proposed date of review of the 1.5°C goal, set at 2015, may be too late to achieve the necessary scaling up of emissions cuts to achieve this goal.     

Is the onset of the English summer advancing?

British summers are known to have become warmer and drier in recent decades, but has there also been a change in the timing of this season’s beginning, as has occurred for spring? This paper addresses this question by examining records of the first blooming date of early summer flowering plants (phenology) and the timing of first occurrences of warm ‘summer’ temperatures, both events that we associate with the onset of summer. This has revealed that the onset of summer in England has been advancing since the mid 1950s. The occurrence of ‘summer’ temperatures has advanced more than early summer flowering, by eleven and three days respectively in the 1990s compared to the period 1954–1963. This may have encouraged drought or heat wave conditions by prolonging the period of warm temperatures and lower rainfall in which these events occur.     

Is climate change a driver of armed conflict?

The world is generally becoming less violent, but the debate on climate change raises the specter of a new source of instability and conflict. In this field, the policy debate is running well ahead of its academic foundation—and sometimes even contrary to the best evidence. Although comparative research on security implications of climate change is rapidly expanding, major gaps in knowledge still exist. Taken together, extant studies provide mostly inconclusive insights, with contradictory or weak demonstrated effects of climate variability and change on armed conflict. This article reviews the empirical literature on short-term climate/environmental change and intrastate conflict, with special attention to possible insecurity consequences of precipitation and temperature anomalies and weather-related natural disasters. Based on this assessment, it outlines priorities for future research in this area.     

Hypothesis on a possible role of El Ni?o in the occurrence of influenza pandemics

The El Ni?o phenomenon is the Earth??s strongest climatic fluctuation on an interannual timescale and has a quasi-global impact, although originating in the tropical Pacific Ocean. A very strong El Ni?o is recognized to cause extreme dryness and wetness in different parts of the world. We show that all the eight well-documented influenza pandemics, starting from the first certain one documented in ad 1580, originated in China and in Russia, a few years after the occurrence of a very strong or after a prolonged strong/moderate El Ni?o event. At present, the next El Ni?o will probably occur at the beginning of 2013 (Mazzarella et al. Theor Appl Climatol 100:23?C27, 2010), and this forecast may suggest to be well prepared to take appropriate precautionary epidemiological measures.     

Objective forecasting of frost using locally‐observed meteorological parameters

Abstract

An objective scheme for forecasting frost is derived using scatter diagrams of meteorological parameters observed at 20 h local time at a station in the western Jezreel Valley of Zsrael. Verifîcation based on independent data was highly consistent with probabilities of frost versus no‐frost predicted by the suggested procedure.     

On the importance of initializing the stochastic part of the atmosphere for forecasting the 1997/1998 El Ni?o

The importance of initializing atmospheric intra-seasonal (stochastic) variations for prediction of the onset of the 1997/1998 El Ni?o is examined using the Australian Bureau of Meteorology coupled seasonal forecast model. A suite of 9-month forecasts was initialized on the 1st December 1996. Observed ocean initial conditions were used together with five different atmospheric initial conditions that sample a range of possible initial states of intra-seasonal (stochastic) variability, especially the Madden-Julian Oscillation (MJO), which is considered the primary stochastic variability of relevance to El Ni?o evolution. The atmospheric initial states were generated from a suite of atmosphere-only integrations forced by observed sea surface temperatures (SST). To the extent that low frequency variability of the tropical atmosphere is forced by slow variations in SST, these atmospheric states should all represent realistic low frequency atmospheric variability that was present in December 1996. However, to the extent that intra-seasonal variability is not constrained by SST, they should capture a range of intra-seasonal states, especially variations in the activity, phase and amplitude of the MJO. For each of these five states, a 20-member ensemble of coupled model forecasts was generated by the addition of small random perturbations to the SST field at the initial time. The ensemble mean from all five sets of forecasts resulted in El Ni?o but three of the sets produced substantially greater warming by months 4?C5 in the NINO3.4 region compared to the other two. The warmer group stemmed from stronger intra-seasonal westerly wind anomalies associated with the MJO that propagated eastward into the central Pacific during the first 1?C2?months of the forecast. These were largely absent in the colder group; the weakest of the colder group developed strong easterly wind anomalies, relative to the grand ensemble mean, that propagated into the central Pacific early in the forecast, thereby generating significantly weaker downwelling Kelvin waves in comparison to the warmer group. The strong reduction in downwelling Kelvin waves in the weakest case acted to limit the warming in the eastern Pacific, resulting in a ??Modoki?? type El Ni?o that is more focused in the central Pacific. Our results suggest that the intra-seasonal stochastic component of the atmospheric initial condition has an important and potentially predictable impact on the forecasts of the initial warming and flavour of the 1997/1998 El Ni?o. However, to the extent that atmospheric intra-seasonal variability is not predictable beyond a month or two, these results imply a limit to the accuracy with which the strength and perhaps the spatial distribution of an El Ni?o can ultimately be predicted. These results do not preclude a predictable role of the MJO and other intra-seasonal stochastic variability at longer lead times if some aspects of the stochastic variability are preconditioned by the evolving state of El Ni?o or other low frequency boundary forcing.     

Why Is the Climate Forcing of Sulfate Aerosols So Uncertain?

l. IntroductionAlthough the aerosol has been recognized as an important factor which has innuence onthe past, present and future climate for a long time, it still has much uncertainty in assessingits climate forcing. The direct radiative forcing of sulfate aerosols has been estimated rangingfrom --0.3 W/ m2 to --0.9 W/ m2 in recent publications (Charlson et al., l992, Kiehl andBriegleb l993; Taylor and Penner 1994, Boucher and Anderson l995, Kieh1 and Rodhe l995;Chuang et al., l997, Penne…     

When does economic development promote mitigation and why?

Is economic development compatible with mitigation? On the one hand, development should promote effective climate policy by enhancing states’ capacities for mitigation. On the other hand, economic growth creates more demand for production, thereby inhibiting emissions reduction. These arguments are often reconciled in the environmental Kuznets curve (EKC) thesis. According to this approach, development initially increases emissions in poor economies, but begins to lower emissions after a country has attained a certain level of development.

The aim of this article is to determine empirically whether the EKC hypothesis seems plausible in light of emissions trends over the birth and implementation of the Kyoto Protocol. Drawing on data from the World Bank World Development Indicators and World Resources Institute Climate Data Explorer, it conducts a large-N investigation of the emissions behaviour of 120 countries from 1990 to 2012. While several quantitative studies have found that economic factors influence emissions activity, this article goes beyond existing research by employing a more sophisticated – multilevel – research design to determine whether economic development: (a) continues to be a significant driver once country-level clustering is accounted for and (b) has different effects on different countries. The results of this article indicate that, even after we account for country-level clustering and hold constant the other main putative drivers of emissions activity, economic development tends to inhibit emissions reduction. They also provide strong evidence that emissions trends resemble the EKC, with development significantly constraining emissions reduction in the South and promoting it in the North.

POLICY RELEVANCE

This article contributes to the understanding of the (changing) role of economic development in shaping emissions activity. It demonstrates the need for a contextualized, country-specific approach for evaluating the effectiveness of economic development in promoting emissions reduction and uncovers new evidence in support of the EKC hypothesis.     

Advances in research and forecasting of tropical cyclones from 1963–2013

A review of progress over the past 50 years in observing and forecasting of tropical cyclones is presented. Tremendous progress has been made in track forecasting in the past 20 years with the improvement in numerical model guidance and the use of consensus forecasting, and this has contributed to a number of warning centers now issuing five-day track forecasts that are as accurate as three-day forecasts of a decade ago. Techniques are now available to specify the track forecast uncertainty for assessing the risk of a tropical cyclone. With the advent of five-day forecasts, a focus on improved understanding of formation has led to two field experiments. A recent advance has been in extended-range (5–30 days) forecasts of tropical cyclone events (formations and tracks) in the western North Pacific from the ECMWF 32-day ensemble predictions. This advance is a contribution to a goal of seamless forecasting from one day to a season for tropical cyclones. Little progress has been made in intensity forecasting, although the Hurricane Forecast Improvement Project in the United States and recent field experiments may offer some future advances. Some advances in forecasting tropical cyclone impacts such as storm surge, surface waves, and precipitation have been achieved. Future opportunities for continued advances are possible such that improved warnings can lead to reductions in losses of lives and minimizing damages from tropical cyclones.     

Is Canadian cloudiness increasing?

Abstract

Cloud amount records for the Canadian mid‐latitudes have been analysed in the context of a “warming world” analogue model that compares records of two 20‐year periods. The cloud amounts increase over practically all these regions while temperatures rise. This historical data set has also been extended temporally to permit analysis of high‐latitude cloudiness trends. These are of particular interest in the “fingerprinting” of CO₂‐induced climatic change. Station records from the Canadian Arctic show distinctive increases in total cloud amount in the last forty years especially in the summer season. This result, unlike the historical analogue analysis, seems to be decoupled from temperature changes.     

The self-organizing methods of long-term forecasting (I) — GMDH and GMPSC model

Summary First, the Group Method of Data Handling (GMDH) algorithm, a self-organizing method for constructing higher order regression, is applied to build a model for long-term forecasting. Then, the Group Method of Phase Space Component (GMPSC) model is set up based on chaos theory and GMDH. Several case studies show that both GMDH and GMPSC provide an efficient and potentially useful tool for non-linear time series modeling.Supported by the NKPFR Climate Dynamics and Climate Prediction Theory.     

Agrometeorological models for forecasting the qualitative attributes of “Valência” oranges

Forecasting is the act of predicting unknown future events using available data. Estimating, in contrast, uses data to simulate an actual condition. Brazil is the world’s largest producer of oranges, and the state of São Paulo is the largest producer in Brazil. The “Valência” orange is among the most common cultivars in the state. We analyzed the influence of monthly meteorological variables during the growth cycle of Valência oranges grafted onto “Rangpur” lime rootstocks (VACR) for São Paulo, and developed monthly agrometeorological models for forecasting the qualitative attributes of VACR in mature orchard. For fruits per box for all months, the best accuracy was of 0.84 % and the minimum forecast range of 4 months. For the relation between °brix and juice acidity (RATIO) the best accuracy was of 0.69 % and the minimum forecast range of 5 months. Minimum, mean and maximum air temperatures, and relative evapotranspiration were the most important variables in the models.     

Is interactive air sea coupling relevant for simulating the future climate of Europe?

Climate Dynamics - The majority of regional climate change assessments for the Euro-CORDEX region is based on high resolution atmosphere models. These models use prescribed lower boundary...     

Is robustness really robust? How different definitions of robustness impact decision-making under climate change

Robust decision-making is being increasingly used to support environmental resources decisions and policy analysis under changing climate and society. In this context, a robust decision is a decision that is as much as possible insensitive to a large degree of uncertainty and ensures certain performance across multiple plausible futures. Yet, the concept of robustness is neither unique nor static. Multiple robustness metrics, such as maximin, optimism-pessimism, max regret, have been proposed in the literature, reflecting diverse optimistic/pessimistic attitudes by the decision maker. Further, these attitudes can evolve in time as a response to sequences of favorable (or adverse) events, inducing possible dynamic changes in the robustness metrics. In this paper, we explore the impact of alternative definitions of robustness and their evolution in time for a case of water resources system management under changing climate. We study the decisions of the Lake Como operator, who is called to regulate the lake by balancing irrigation supply and flood control, under an ensemble of climate change scenarios. Results show a considerable variability in the system performance across multiple robustness metrics. In fact, the mis-definition of the actual decision maker’s attitude biases the simulation of its future decisions and produces a general underestimation of the system performance. The analysis of the dynamic evolution of the decision maker’s preferences further confirms the potentially strong impact of changing robustness definition on the decision-making outcomes. Climate change impact assessment studies should therefore include the definition of robustness among the uncertain parameters of the problem in order to analyze future human decisions under uncertainty.     

Is public awareness and perceived threat of climate change associated with governmental mitigation targets?

Social scientists and science communicators are concerned about the apparent discrepancy between the scientific consensus on climate change (Anderegg et al. Proc Natl Acad Sci 107:12107–12109, 2010; Doran and Zimmerman EOS Trans Am Geophys Union 90:22–3, 2009) and the general public’s views (Knight Environ Sociol 2:101–113, 2016; Lee et al. Nat Clim Chang 5:1014–1020, 2015). It is reasoned that increased public awareness and perceived threat of climate change may pressure governments to enact policy to counteract climate change (e.g. setting stringent carbon emissions targets). Despite a logical link between public awareness and government-set emissions targets, this relationship remains untested. We examined the relationship between public awareness about and perceived threat of climate change and governmental emissions targets across 71 countries and 1 region. We found a positive association between the proportions of a country’s population that are aware of climate change and the unconditional emissions reduction targets set by that country in the Paris Agreement (Rogelj et al. Nature 534:631–639, 2016). However, the proportion of people in a country who perceive climate change as a personal threat was not associated with higher emissions reduction targets. Our results suggest that public awareness may be an important part of garnering the public support required for policies designed to mitigate climate change to succeed.     

Is the interdecadal variation of the summer rainfall over eastern China associated with SST?

The present study examined the major features of the interdecadal variation of the summer rainfall over eastern China (IVRC) and the possible association with sea surface temperature (SST). We noted that the first leading mode of IVRC (accounting for nearly half of the total variance and with maximum loading for the summer rainfall anomalies over South China) may be not forced by SST. On the other hand, the second and third leading modes [accounting for 17.1 and 13.6 % of the total variance and mainly associated with the summer rainfall anomalies over the Yangtze River valley (YRV) and North China, respectively] in some extent are forced by SST anomalies. These observational results are confirmed by atmospheric general circulation model (AGCM) simulations forced by observed SST. By eliminating the internal dynamical process driven rainfall though ensemble mean, the simulations further suggest an overall enhancement of the intensity of IVRC in the corresponding ensemble mean, especially in the YRV and North China regions, but not in South China. That implies the different role of SST in driving IVRC over different regions.