Atmospheric Disturbance Characteristics in the Lower-middle Stratosphere Inferred from Observations by the Round-Trip Intelligent Sounding System (RTISS) in China

Through multi-order structure function analysis and singularity measurement,the Hurst index and intermittent parameter are obtained to quantitatively describe the characteristics of atmospheric disturbance based on the round-trip intelligent sounding system(RTISS)in the lower-middle stratosphere.According to the third-order structure function,small-scale gravity waves are classified into three states:stable,unstable,and accompanied by turbulence.The evolution of gravity waves is reflected by the variation of the third-order structure function over time,and the generation of turbulence is also observed.The atmospheric disturbance intensity parameter RT is defined in this paper and contains both wave disturbance(H₁)and random intermittency(C₁).RT is considered to reflect the characteristics of atmospheric disturbance more reasonably than either of the above two alone.In addition,by obtaining the horizontal wavenumber spectrum from the flat-floating stage and the vertical wavenumber spectrum from the ascending and descending stages at the height range of18-24 km,we found that when the gravity wave activity is significantly enhanced in the horizontal direction,the amplitude of the vertical wavenumber spectrum below is significantly larger,which shows a significant impact of gravity wave activity on the atmospheric environment below.     

Improving Simulations of Vegetation Dynamics over the Tibetan Plateau: Role of Atmospheric Forcing Data and Spatial Resolution

The efficacy of vegetation dynamics simulations in offline land surface models (LSMs) largely depends on the quality and spatial resolution of meteorological forcing data. In this study, the Princeton Global Meteorological Forcing Data (PMFD) and the high spatial resolution and upscaled China Meteorological Forcing Data (CMFD) were used to drive the Simplified Simple Biosphere model version 4/Top-down Representation of Interactive Foliage and Flora Including Dynamics (SSiB4/TRIFFID) and investigate how meteorological forcing datasets with different spatial resolutions affect simulations over the Tibetan Plateau (TP), a region with complex topography and sparse observations. By comparing the monthly Leaf Area Index (LAI) and Gross Primary Production (GPP) against observations, we found that SSiB4/TRIFFID driven by upscaled CMFD improved the performance in simulating the spatial distributions of LAI and GPP over the TP, reducing RMSEs by 24.3% and 20.5%, respectively. The multi-year averaged GPP decreased from 364.68 gC \begin{document}${\mathrm{m}}^{-2}\;{\mathrm{y}\mathrm{r}}^{-1}$\end{document} to 241.21 gC \begin{document}${\mathrm{m}}^{-2}\;{\mathrm{y}\mathrm{r}}^{-1}$\end{document} with the percentage bias dropping from 50.2% to –1.7%. When using the high spatial resolution CMFD, the RMSEs of the spatial distributions of LAI and GPP simulations were further reduced by 7.5% and 9.5%, respectively. This study highlights the importance of more realistic and high-resolution forcing data in simulating vegetation growth and carbon exchange between the atmosphere and biosphere over the TP.     

Aerosol-Cloud-Precipitation Interactions in a Closed-cell and Non-homogenous MBL Stratocumulus Cloud

A closed-cell marine stratocumulus case during the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) aircraft field campaign is selected to examine the heterogeneities of cloud and drizzle microphysical properties and the aerosol-cloud-precipitation interactions. The spatial and vertical variabilities of cloud and drizzle microphysics are found in two different sets of flight legs: Leg-1 and Leg-2, which are parallel and perpendicular to the cloud propagation, respectively. The cloud along Leg-2 was close to adiabatic, where cloud-droplet effective radius and liquid water content linearly increase from cloud base to cloud top with less drizzle. The cloud along Leg-1 was sub-adiabatic with lower cloud-droplet number concentration and larger cloud-droplet effective, but higher drizzle droplet number concentration, larger drizzle droplet median diameter and drizzle liquid water content. The heavier drizzle frequency and intensity on Leg-1 were enhanced by the collision-coalescence processes within cloud due to strong turbulence. The sub-cloud precipitation rate on Leg-1 was significantly higher than that along Leg-2. As a result, the sub-cloud accumulation mode aerosols and CCN on Leg-1 were depleted, but the coarse model aerosols increased. This further leads to a counter-intuitive phenomenon that the CCN is less than cloud-droplet number concentration for Leg-1. The average CCN loss rates are ?3.89 \begin{document}$\mathrm{c}{\mathrm{m}}^{-3}\;{\mathrm{h}}^{-1}$\end{document} and ?0.77 \begin{document}$\mathrm{c}{\mathrm{m}}^{-3}\;{\mathrm{h}}^{-1}$\end{document} on Leg-1 and Leg-2, respectively. The cloud and drizzle heterogeneities inside the same stratocumulus can significantly alter the sub-cloud aerosols and CCN budget. Hence it should be treated with caution in the aircraft assessment of aerosol-cloud-precipitation interactions.     

CAS FGOALS-f3-H Dataset for the High-Resolution Model Intercomparison Project (HighResMIP) Tier 2

Following the High-Resolution Model Intercomparison Project (HighResMIP) Tier 2 protocol under the Coupled Model Intercomparison Project Phase 6 (CMIP6), three numerical experiments are conducted with the Chinese Academy of Sciences Flexible Global Ocean-Atmosphere-Land System Model, version f3-H (CAS FGOALS-f3-H), and a 101-year (1950–2050) global high-resolution simulation dataset is presented in this study. The basic configuration of the FGOALS-f3-H model and numerical experiments design are briefly described, and then the historical simulation is validated. Forced by observed radiative agents from 1950 to 2014, the coupled model essentially reproduces the observed long-term trends of temperature, precipitation, and sea ice extent, as well as the large-scale pattern of temperature and precipitation. With an approximate 0.25o horizontal resolution in the atmosphere and 0.1° in the ocean, the coupled models also simulate energetic western boundary currents and the Antarctic Circulation Current (ACC), reasonable characteristics of extreme precipitation, and realistic frontal scale air-sea interaction. The dataset and supporting detailed information have been published in the Earth System Grid Federation (ESGF, https://esgf-node.llnl.gov/projects/cmip6/).     

The role of money and the financial sector in energy-economy models used for assessing climate and energy policy

This article outlines a critical gap in the assessment methodology used to estimate the macroeconomic costs and benefits of climate and energy policy, which could lead to misleading information being used for policy-making. We show that the Computable General Equilibrium (CGE) models that are typically used for assessing climate policy use assumptions about the financial system that sit at odds with the observed reality. These assumptions lead to ‘crowding out’ of capital and, because of the way the models are constructed, negative economic impacts (in terms of gross domestic product (GDP) and welfare) from climate policy in virtually all cases.

In contrast, macro-econometric models, which follow non-equilibrium economic theory and adopt a more empirical approach, apply a treatment of the financial system that is more consistent with reality. Although these models also have major limitations, they show that green investment need not crowd out investment in other parts of the economy – and may therefore offer an economic stimulus. Our conclusion is that improvements in both modelling approaches should be sought with some urgency – both to provide a better assessment of potential climate and energy policy and to improve understanding of the dynamics of the global financial system more generally.

POLICY RELEVANCE

This article discusses the treatment of the financial system in the macroeconomic models that are used in assessments of climate and energy policy. It shows major limitations in approach that could result in misleading information being provided to policy-makers.     

Benefit cost analysis,resilience and climate change

Applying a resilience theory framework, land transport funding in New Zealand is used to show how benefit cost analysis can reinforce a preference for maintaining existing economic and social systems when, instead, consideration of more socially disruptive options may be required. In this context, resilience is seen as the ability to maintain transport systems rather than the ability to reduce the probability of climate change. The latter role of resilience attempts to identify thresholds and regime shifts, and so critiques decision-making processes, while the former privileges social stability, thereby reducing the range of potentially useful emission mitigation options to be considered.

Policy relevance

Transitioning to a lower-carbon future requires policy formulation that challenges business-as-usual assumptions. Benefit cost analysis can be applied in ways that create barriers to such transitioning. The New Zealand case study identifies the conditions under which this can be the case. That benefit cost analysis could undermine the potential of resilience theory and application to identify low-carbon emission pathways is of concern to policy makers globally.     

Power,coalitions and institutional change in South African climate policy

This paper examines power relations, coalitions and conflicts that drive and hinder institutional change in South African climate policy. The analysis finds that the most contested climate policies are those that create distributional conflicts where powerful, non-poor actors will potentially experience real losses to their fossil fuel-based operations. This finding opposes the assumption of competing objectives between emissions and poverty reduction. Yet, actors use discourse that relates to potentially competing objectives between emissions reductions, jobs, poverty reduction and economic welfare.

The analysis relates to the broader questions on how to address public policy problems that affect the two objectives of mitigating climate change and simultaneously boosting socio-economic development. South Africa is a middle-income country that represents the challenge of accommodating simultaneous efforts for emissions and poverty reduction.

Institutional change has been constrained especially in the process towards establishing climate budgets and a carbon tax. The opposing coalitions have succeeded in delaying the implementation of these processes, as a result of unequal power relations. Institutional change in South African climate policy can be predominantly characterized as layering with elements of policy innovation. New policies build on existing regulations in all three cases of climate policy examined: the climate change response white paper, the carbon tax and the renewable energy programme. Unbalanced power relations between coalitions of support in government and civil society and opposition mainly from the affected industry result in very fragile institutional change.

Key policy insights

• The South African government has managed to drive institutional change in climate policy significantly over the past 7 years.

• Powerful coalitions of coal-related industries and their lobbies have constrained institutional change and managed to delay the implementation of carbon pricing measures.

• A successfully managed renewable energy programme has started to transform a coal- and nuclear-powered electricity sector towards integrating sustainable energy technologies. The programme is vulnerable to intergovernmental opposition and requires management at the highest political levels.

• Potential conflict with poverty reduction measures is not a major concern that actively hinders institutional change towards climate objectives. Predominantly non-poor actors frequently use poverty-related discourse to elevate their interests to issues of public concern.

     

Scenarios for a 2 °C world: a trade-linked input–output model with high sector detail

In this study a scenario model is used to examine if foreseen technological developments are capable of reducing CO₂ emissions in 2050 to a level consistent with United Nations Framework Convention on Climate Change (UNFCCC) agreements, which aim at maximizing the temperature rise to 2 °C compared to pre-industrial levels. The model is based on a detailed global environmentally extended supply–use table (EE SUT) for the year 2000, called EXIOBASE. This global EE SUT allows calculating how the final demand in each region drives activities in production sectors, and hence related CO₂ emissions, in each region. Using this SUT framework, three scenarios have been constructed for the year 2050. The first is a business-as-usual scenario (BAU), which takes into account population, economic growth, and efficiency improvements. The second is a techno-scenario (TS), adding feasible and probable climate mitigation technologies to the BAU scenario. The third is the towards-2-degrees scenario (2DS), with a demand shift or growth reduction scenario added to the TS to create a 2 °C scenario. The emission results of the three scenarios are roughly in line with outcomes of typical scenarios from integrated assessment models. Our approach indicates that the 2 °C target seems difficult to reach with advanced CO₂ emission reduction technologies alone.

Policy relevance

The overall outlook in this scenario study is not optimistic. We show that CO₂ emissions from steel and cement production and air and sea transport will become dominant in 2050. They are difficult to reduce further. Using biofuels in air and sea transport will probably be problematic due to the fact that agricultural production largely will be needed to feed a rising global population and biofuel use for electricity production grows substantially in 2050. It seems that a more pervasive pressure towards emission reduction is required, also influencing the basic fabric of society in terms of types and volumes of energy use, materials use, and transport. Reducing envisaged growth levels, hence reducing global gross domestic product (GDP) per capita, might be one final contribution needed for moving to the 2 °C target, but is not on political agendas now.     

Indigenous community benefits from a de-centralized approach to REDD+ in Brazil

Successful efforts of indigenous groups to reduce emissions from deforestation and forest degradation in developing countries (REDD+) will likely vary with how the initiatives are designed and implemented. Whether REDD+ initiatives are carried out by national governments or decentralized to sub-national or project-level institutions with a nested approach could be of great consequence. I describe the Suruí Forest Carbon Project in Amazonian Brazil, one of the first REDD+ pilot projects implemented with indigenous people in the world. I emphasize (1) how enfranchisement of community members in the policy-planning process, fund management, and carbon baseline establishment increased project reliability and equity, and (2) how the project's quality would have likely been diminished if implemented under a centralized REDD+ scheme.

Policy relevance

This article explores a decentralized REDD+ intervention established in an indigenous land in Brazil. It expands the theoretical discussions on REDD+ governance and highlights how centralized REDD+ programmes are likely to be less effective than project-level interventions assisted by NGOs in terms of social benefits and community engagement. Additionally, the case study described can serve as reference for the design of critical social and technical components of REDD+.