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Abstract Tropical high cloud cover decreases with surface warming in most general circulation models. This reduction, according to the “stability‐iris” hypothesis, is thermodynamically controlled and linked to a decrease in the radiatively‐driven clear‐sky convergence, when the peak anvil clouds rise because of the rising isotherms. The influence of the large‐scale dynamical changes on the tropical high cloud fraction remains difficult to disentangle from the local thermodynamic influence, given that the mean meridional circulation remains inextricably tied to the local thermodynamic structure of the atmosphere. However, using idealized general circulation model simulations, we propose a novel method to segregate the dynamical impact from the thermodynamic impact on the tropical high cloud fraction. To this end, our investigation primarily focuses on the mechanisms underpinning changes in the high cloud cover in the deep tropics in response to extratropical surface warming, when the tropical sea surface temperatures remain invariant. Net convective detrainment of ice cloud condensates decreases at the peak detrainment region, without a rise in its altitude. We also find that the importance of depositional growth of ice cloud condensates in controlling the high cloud fraction response in the deep tropics varies with altitude.

Convective processes are crucial in shaping exoplanetary atmospheres but are computationally expensive to simulate directly. A novel technique of simulating moist convection on tidally locked exoplanets is to use a global 3D model with a stretched mesh. This allows us to locally refine the model resolution to 4.7 km and resolve fine-scale convective processes without relying on parameterizations. We explore the impact of mesh stretching on the climate of a slowly rotating TRAPPIST-1e-like planet, assuming it is 1:1 tidally locked. In the stretched-mesh simulation with explicit convection, the climate is 5 K colder and 25% drier than that in the simulations with parameterized convection(with both stretched and quasi-uniform meshes). This is due to the increased cloud reflectivity—because of an increase in low-level cloudiness—and exacerbated by the diminished greenhouse effect due to less water vapor. At the same time, our stretched-mesh simulations reproduce the key characteristics of the global climate of tidally locked rocky exoplanets, without any noticeable numerical artifacts. Our methodology opens an exciting and computationally feasible avenue for improving our understanding of 3D mixing in exoplanetary atmospheres. Our study also demonstrates the feasibility of a global stretched-mesh configuration for LFRic-Atmosphere, the next-generation Met Office climate and weather model.

Abstract Background Caledonian Stadium, the main mass temporary shelter for homeless people in the City of Tshwane, was created as a local response to the imperatives of the novel coronavirus disease (COVID-19) National State of Disaster lockdown in South Africa. This is a case study of the coordinated emergency healthcare response provided by the University of Pretoria’s Department of Family Medicine between 24 March and 6 April 2020. Methods This study uses a narrative approach to restory situated, transient, partial and provisional knowledge. Analysis is based on documented data and iteratively triangulated interviews on the operational experiences of selected healthcare first responders directly involved in the shelter. Results The impending lockdown generated intense interactions by UP-DFM to prepare for the provision of COVID-19 and essential generalist primary with partners involved in the Community Oriented Substance Use Programme (COSUP). With approximately 2000 people at the shelter at its peak, the numbers exceeded expectations. Throughout, while government officials tried to secure bedding, food and toilets, the shelter was poorly equipped and without onsite management. The COSUP clinical team prioritised opioid substitution therapy using methadone and COVID-19 screening over generalist healthcare to manage withdrawal and contain tension and anxiety. COSUP and its partners helped the city plan and implement the safe re-sheltering of all Caledonian residents. Conclusion The Caledonian shelter is an account of organisational resilience in the face of homelessness and substance use emergencies triggered by lockdown. Through community-oriented, bottom-up self-organisation, a clinically led team navigated a response to the immediate needs of people who are homeless and/or use drugs that evolved into a more sustainable intervention. Key lessons learnt were the importance of communicating with people directly affected by emergencies, the value of using methadone to reduce harms during emergencies and the imperative of including OST in essential primary healthcare.

In this study, the authors investigate in the influence of atmospheric dust on the habitability of exoplanets. They find that atmospheric dust may postpone planetary water loss; for tidally locked planets in particular, dust can significantly widen the habitable zone by cooling the day side and warming the night side.

Century-long observed gridded land precipitation datasets are a cornerstone of hydrometeorological research. But recent work has suggested that observed Northern Hemisphere midlatitude (NHML) land mean precipitation does not show evidence of an expected negative response to mid-twentieth-century aerosol forcing. Utilizing observed river discharges, the observed runoff is calculated and compared with observed land precipitation. The results show a near-zero twentieth-century trend in observed NHML land mean runoff, in contrast to the significant positive trend in observed NHML land mean precipitation. However, precipitation and runoff share common interannual and decadal variability. An obvious split, or breakpoint, is found in the NHML land mean runoff-precipitation relationship in the 1930s. Using runoff simulated by six land surface models (LSMs), which are driven by the observed precipitation dataset, such breakpoints are absent. These findings support previous hypotheses that inhomogeneities exist in the early-twentieth-century NHML land mean precipitation record. Adjusting the observed precipitation record according to the observed runoff record largely accounts for the departure of the observed precipitation response from that predicted given the real-world aerosol forcing estimate, more than halving the discrepancy from about 6 to around 2 W m-2. Consideration of complementary observed runoff adds support to the suggestion that NHML-wide early-twentieth-century precipitation observations are unsuitable for climate change studies. The agreement between precipitation and runoff over Europe, however, is excellent, supporting the use of whole-twentieth-century observed precipitation datasets here.

This short report describes the role that family physicians (FPs) (and family medicine registrars) played to provide care for the homeless people in shelters (both temporary and permanent) during the coronavirus disease 2019 (COVID-19) lockdown in the City of Tshwane, South Africa. The lockdown resulted in the establishment of a large number of temporary shelters. The FPs took on the task to provide comprehensive and coordinated primary care, whilst extending their activities in terms of data management, quality improvement, capacity building and research. The FPs worked in teams with other healthcare providers and contributed a unique set of skills to the process. This report demonstrates the value of responding quickly and appropriately through communication, cooperation and innovation. It also demonstrates the large number of areas in which FPs can make a difference when engaged appropriately, with the necessary support and collaboration, thus making a positive impact in the already overburdened health services.

Convective processes are crucial in shaping exoplanetary atmospheres but are computationally expensive to simulate directly. A novel technique of simulating moist convection on tidally locked exoplanets is to use a global 3D model with a stretched mesh. This allows us to locally refine the model resolution to 4.7 km and resolve fine-scale convective processes without relying on parameterizations. We explore the impact of mesh stretching on the climate of a slowly rotating TRAPPIST-1e-like planet, assuming it is 1:1 tidally locked. In the stretched-mesh simulation with explicit convection, the climate is 5 K colder and 25% drier than that in the simulations with parameterized convection(with both stretched and quasi-uniform meshes). This is due to the increased cloud reflectivity—because of an increase in low-level cloudiness—and exacerbated by the diminished greenhouse effect due to less water vapor. At the same time, our stretched-mesh simulations reproduce the key characteristics of the global climate of tidally locked rocky exoplanets, without any noticeable numerical artifacts. Our methodology opens an exciting and computationally feasible avenue for improving our understanding of 3D mixing in exoplanetary atmospheres. Our study also demonstrates the feasibility of a global stretched-mesh configuration for LFRic-Atmosphere, the next-generation Met Office climate and weather model. [ABSTRACT FROM AUTHOR]

South Africa envisages a community-orientated approach to primary health care (PHC). Family physicians and primary care doctors have important roles to play in leading, implementing, supporting and maintaining community-orientated primary care (COPC). In this article, we define COPC, its key principles and approaches to implementing it in health services. Following this we describe the key competencies expected of family physicians and primary care doctors in leading and supporting its implementation; providing clinical support to the PHC teams and linking these teams to other parts of the health system, other sectors and the community. The required knowledge and skills underlying these competencies are also discussed and some specific tools included.

No abstract available

In order to assess observational evidence for potential atmospheric biosignatures on exoplanets, it will be essential to test whether spectral fingerprints from multiple gases can be explained by abiotic or biotic-only processes. Here, we develop and apply a coupled 1D atmosphere-ocean-ecosystem model to understand how primitive biospheres, which exploit abiotic sources of H |$_2$|⁠ , CO, and O |$_2$|⁠ , could influence the atmospheric composition of rocky terrestrial exoplanets. We apply this to the Earth at 3.8 Ga and to TRAPPIST-1e. We focus on metabolisms that evolved before the evolution of oxygenic photosynthesis, which consume H |$_2$| and CO and produce potentially detectable levels of CH |$_4$|⁠. O |$_2$| -consuming metabolisms are also considered for TRAPPIST-1e, as abiotic O |$_2$| production is predicted on M-dwarf orbiting planets. We show that these biospheres can lead to high levels of surface O |$_2$| (approximately 1–5 per cent) as a result of CO consumption, which could allow high O |$_2$| scenarios, by removing the main loss mechanisms of atomic oxygen. Increasing stratospheric temperatures, which increases atmospheric OH can reduce the likelihood of such a state forming. O |$_2$| -consuming metabolisms could also lower O |$_2$| levels to around 10 ppm and support a productive biosphere at low reductant inputs. Using predicted transmission spectral features from CH |$_4$|⁠ , CO, O |$_2$| /O |$_3$|⁠ , and CO |$_2$| across the hypothesis space for tectonic reductant input, we show that biotically produced CH |$_4$| may only be detectable at high reductant inputs. CO is also likely to be a dominant feature in transmission spectra for planets orbiting M-dwarfs, which could reduce the confidence in any potential biosignature observations linked to these biospheres. [ABSTRACT FROM AUTHOR]

Tropical high cloud cover decreases with surface warming in most general circulation models. This reduction, according to the "stability‐iris" hypothesis, is thermodynamically controlled and linked to a decrease in the radiatively‐driven clear‐sky convergence, when the peak anvil clouds rise because of the rising isotherms. The influence of the large‐scale dynamical changes on the tropical high cloud fraction remains difficult to disentangle from the local thermodynamic influence, given that the mean meridional circulation remains inextricably tied to the local thermodynamic structure of the atmosphere. However, using idealized general circulation model simulations, we propose a novel method to segregate the dynamical impact from the thermodynamic impact on the tropical high cloud fraction. To this end, our investigation primarily focuses on the mechanisms underpinning changes in the high cloud cover in the deep tropics in response to extratropical surface warming, when the tropical sea surface temperatures remain invariant. Net convective detrainment of ice cloud condensates decreases at the peak detrainment region, without a rise in its altitude. We also find that the importance of depositional growth of ice cloud condensates in controlling the high cloud fraction response in the deep tropics varies with altitude. Plain Language Summary: The cloud feedback associated with changes in the tropical high cloud cover is one of the major uncertainties in calculating the current estimates of climate sensitivity, which is a measure of how much the Earth's average surface temperature would increase if we double the amount of atmospheric carbon dioxide. When the surface becomes warmer in the tropics, the tropical high cloud cover decreases. However, this raises an important question: how do circulation changes independent of the temperature changes within the tropics impact the tropical high cloud cover? Using idealized general circulation model simulations, we found that the tropical high cloud fraction decreases as a result of circulation changes induced by extratropical warming, even when the tropical sea surface temperatures are held constant. Both convective and cloud microphysical processes play significant roles in controlling the changes in tropical high cloud fraction, and their relative importance varies with altitude. Understanding the different factors responsible for the changes in high cloud cover is important, as the area covered by these tropical high clouds can affect how much the Earth warms under climate change. Key Points: An indirect weakening of the Hadley circulation decreases the convectively‐detrained ice cloud condensates in the deep tropicsA concurrent reduction in the net vertical transport of water vapor limits the depositional growth of ice cloud condensatesThe relative influence of depositional growth to net convective detrainment on the tropical high cloud response is altitude‐dependent [ABSTRACT FROM AUTHOR]

Background: Globally, rural populations have poorer health and considerably lower levels of access to healthcare compared with urban populations. Although the drive to ensure universal coverage through community healthcare worker programmes has shown significant results elsewhere, their value has yet to be realised in South Africa. Aim: The aim of this study was to determine the potential impact, cost-effectiveness and benefit-to-cost ratio (BCR) of information and communications technology (ICT)-enabled community-oriented primary care (COPC) for rural and remote populations. Setting: The Waterberg district of Limpopo province in South Africa is a rural mining area. The majority of 745 000 population are poor and in poor health. Methods: The modelling considers condition-specific effectiveness, population age and characteristics, health-determined service demand, and costs of delivery and resources. Results: Modelling showed 122 teams can deliver a full ICT-enabled COPC service package to 630 565 eligible people. Annually, at scale, it could yield 35 877 unadjusted life years saved and 994 deaths avoided at an average per capita service cost of R170.37, and R2668 per life year saved. There could be net annual savings of R120 million (R63.4m for Waterberg district) from reduced clinic (110.7m) and hospital outpatient (23 646) attendance and admissions. The service would inject R51.6m into community health worker (CHW) households and approximately R492m into district poverty reduction and economic growth. Conclusion: With a BCR of 3.4, ICT-enabled COPC is an affordable systemic investment in universal, pro-poor, integrated healthcare and makes community-based healthcare delivery particularly compelling in rural and remote areas.

Background: Tuberculosis (TB) is a persistent major public health challenge in South Africa. This article examines the social determinants and demographic factors associated with TB loss to follow-up through the lens of intersectionality. Aim: The aim of this study was to describe and interpret the social determinants and demographic factors associated with TB patients lost to follow-up (LTFU). Setting: Mamelodi, an urban settlement in the South African District of Tshwane. Methods: AitaHealth™ is an Information and Communications Technology (ICT) mobile and web application that is used by community health workers. Data from patients with TB were extracted from the 64 319 households registered on AitaHealth™ over a 3-year period. Univariate and multivariate analyses were used to compare patients who were adherent to TB treatment and those LTFU. Results: Of the 184 351 individuals screened for TB, 788 reported that they were diagnosed with TB (an incidence of 427 cases per 100 000). Of the 704 eligible for inclusion in this analysis, 540 (77%) were on treatment and 164 (23%) were LTFU. The factors associated with LTFU were aged over 60, not having a South African identification document, migration and death in the household, and higher mean household income. Conclusion: The results of this study serve as a reminder to clinicians of the importance of the three-stage assessment (biopsychosocial) in the approach to patients with TB. Understanding the intersection of social determinants and demographic factors helps clinicians and others identify and respond to the specificity of patient, health system and non-health policy issues at play in LTFU.

The East Asian summer monsoon rainfall provides water security and socio‐economic benefit for over 20% of the global population. However, the sources of this rainfall and how it is carried to the East Asian landmass are still uncertain. To address this, atmospheric water sources and pathways associated with the East Asian summer rainfall are identified and quantified in this study using atmospheric water trajectories, calculated with a novel Lagrangian framework. Evaporated water from the East Asian landmass is found to be the major contributor to East Asian rainfall, amounting to local recycling. The results further indicated that the south Indian Ocean is a major non‐local source for rainfall over southern East Asia during June to August. The role of the south Indian Ocean as a source of atmospheric water is one of the major findings of the study and would help in better understanding and predicting the East Asian summer rainfall. Evaporated waters from the Pacific Ocean (particularly the far‐west Pacific Ocean) dominate the non‐local contribution to precipitation over northern East Asia during June to September and over southern East Asian rainfall during September. The spatial structure of the East Asian rainfall is reported to be determined by the atmospheric waters that are evaporated and transported from the non‐local sources. The role of the north Indian Ocean and the South Asian landmass as a source of water for East Asian precipitation is minimal and restricted to southern East Asia. The cross‐equatorial Somali jet and equatorial trade winds associated with the western North Pacific subtropical high are important pathways for East Asian precipitation sourced over the south Indian Ocean and the Pacific Ocean respectively. In contrast, minor roles are attributed to the Bay of Bengal as a source, and midlatitude westerlies as a transport pathway, for East Asian precipitation. [ABSTRACT FROM AUTHOR]

Background: The introduction of community-based services through community health workers is an opportunity to redefine the approach and practice of primary health care. Based on bestpractice community oriented primary care (COPC), a COPC planning toolkit has been developed to model the creation of a community-based tier in an integrated district health system. Aim: The article describes the methodologies and assumptions used to determine workforce numbers and service costs for three scenarios and applies them to the poorest 60% of the population in Gauteng, South Africa. Setting: The study derives from a Gauteng Department of Health, Family Medicine (University of Pretoria) partnership to support information and communication technology (ICT)-enabled COPC through community-based health teams (termed as ward-based outreach teams). Methods: The modelling uses national census age, gender and income data at small area level, provincial facility and national burden of disease data. Service calculations take into account multidimensional poverty, demand-adjusted burden of disease and available work time adjusted for conditions of employment and geography. Results: Assuming the use of ICT for each, a health workforce of 14 819, 17 925 and 7303 is required per scenario (current practice, national norms and full-time employed COPC), respectively. Total service costs for the respective scenarios range from R1.1 billion, through R947 million to R783 million. Conclusion: Modelling shows that delivering ICT-enabled COPC with full-time employees is the optimal scenario. It requires the smallest workforce, is the most economical, even when individual community health worker costs of employment are twice those of current practice, and is systemically the most effective.

The objective of this work was to analyze the influence of cognitive and personality variables in the Decision Making (DM) construct, evaluated by the Iowa Gambling Task (IGT). For this propose, a battery of neuropsychological tests was applied to 116 individuals of both genders between 18 and 35 years olds. The results showed that the IGT performance was not associated to the cognitive variables evaluated, only it has been found moderated relationship between working memory and DM. These outcomes suggest that DM seems to be an independent construct of the “cool” cognitive functions and could be influenced for the emotional or motivational aspects related to “hot” cognitive process. Finally, the DM process seems to be more associated to the ability to avoid punishment than the capacity of evaluate long term benefits.

Managed healthcare, in the context of this study, is defined as a series of management interventions in the healthcare supply chain, aimed at promoting appropriate and necessary care at a cost which is affordable to the consumer. It has evolved precisely because the healthcare supply chain is inefficient, too costly to be affordable to the majority of consumers in South Africa. Since managed healthcare represents a collection of interventions it is probable that these interventions will provoke responses which either support or counter the objectives of the intervening parties. The study focuses on trends which can be quantified in order to demonstrate this process, as well as on qualitative responses from role-players within the system, in order to explain behavioural changes that give rise to these trends. Managed healthcare is a management tool that is used in the private healthcare environment to manage the provision of care. In the past it was based on retrospective intervention and had cost containment as its main focus. Managed healthcare aims to address efficiency and quality of care but has yet to demonstrate measurable outcomes that would significantly impact on its WHO ratings. However, little attention is paid to the relationships and structure of the system within which care is provided and the dynamics that exist between and amongst role-players. The extent to which these relationships have an effect on the outcomes of the Private Healthcare Delivery System in South Africa is a relative unknown quantity. This article describes the research process which endeavours to develop a systemic approach to understand the current challenges in the PHDS better in order to optimise the outcome of it.

Author(s): Xuebin Zhang [1]; Francis W. Zwiers (corresponding author) [1]; Gabriele C. Hegerl [2]; F. Hugo Lambert [3]; Nathan P. Gillett [4]; Susan Solomon [5]; Peter A. Stott [6]; Toru [...]

Projections of future West African monsoon (WAM) precipitation change in response to increasing greenhouse gases are uncertain, and an improved understanding of the drivers of WAM precipitation change is needed to help aid model development and better inform adaptation policies in the region. This paper addresses one of those drivers, the direct radiative effect of increased CO2 (i.e., the impact of increased CO2 in the absence of SST warming and changes in plant physiology). An atmosphere-only model is used to examine both the equilibrium response and the evolution of the change over the days following the instantaneous CO2 increase. In response to the direct radiative effect, WAM precipitation increases due to a weakening of the shallow meridional circulation over North Africa, advecting less dry air into the convective column associated with the monsoon. Changes in the shallow circulation are associated with atmospheric and surface warming patterns over North Africa. A large-scale atmospheric warming pattern, whereby North Africa warms more than the monsoon region, leads to a northward shift in the Saharan heat low. In response to increased precipitation in the Sahel, local soil moisture feedbacks play a key role in determining the low-level circulation change and the location of the intertropical discontinuity. The large-scale warming patterns over North Africa result from differing levels of constraint applied by convective quasi-equilibrium. While this constraint acts strongly in the equatorial WAM region, preventing the region from warming in response to the direct radiative effect, North Africa is not strongly constrained and is therefore able to warm. [ABSTRACT FROM AUTHOR]

Identification of habitable planets beyond our solar system is a key goal of current and future space missions. Yet habitability depends not only on the stellar irradiance, but equally on constituent parts of the planetary atmosphere. Here we show, for the first time, that radiatively active mineral dust will have a significant impact on the habitability of Earth-like exoplanets. On tidally-locked planets, dust cools the day-side and warms the night-side, significantly widening the habitable zone. Independent of orbital configuration, we suggest that airborne dust can postpone planetary water loss at the inner edge of the habitable zone, through a feedback involving decreasing ocean coverage and increased dust loading. The inclusion of dust significantly obscures key biomarker gases (e.g. ozone, methane) in simulated transmission spectra, implying an important influence on the interpretation of observations. We demonstrate that future observational and theoretical studies of terrestrial exoplanets must consider the effect of dust. In this study, the authors investigate in the influence of atmospheric dust on the habitability of exoplanets. They find that atmospheric dust may postpone planetary water loss; for tidally locked planets in particular, dust can significantly widen the habitable zone by cooling the day side and warming the night side. [ABSTRACT FROM AUTHOR]

Using a 3D general circulation model (GCM), we investigate the sensitivity of the climate of tidally locked Earthlike exoplanets, Trappist-1e and Proxima Centauri b, to the choice of a convection parameterization. Compared to a mass-flux convection parameterization, a simplified convection adjustment parameterization leads to a >60% decrease of the cloud albedo, increasing the mean dayside temperature by. The representation of convection also affects the atmospheric conditions of the night side, via a change in planetary-scale wave patterns. As a result, using the convection adjustment scheme makes the nightside cold traps warmer by 17–36 K for the planets in our simulations. The day–night thermal contrast is sensitive to the representation of convection in 3D GCM simulations, so caution should be taken when interpreting emission phase curves. The choice of convection treatment, however, does not alter the simulated climate enough to result in a departure from habitable conditions, at least for the atmospheric composition and planetary parameters used in our study. The near-surface conditions both in the Trappist-1e and Proxima b cases remain temperate, allowing for an active water cycle. We further advance our analysis using high-resolution model experiments, in which atmospheric convection is simulated explicitly. Our results suggest that in a hypothetical global convection-permitting simulation, the surface temperature contrast would be higher than in the coarse-resolution simulations with parameterized convection. In other words, models with parameterized convection may overestimate the inter-hemispheric heat redistribution efficiency. [ABSTRACT FROM AUTHOR]

This study investigates how the direct effects of CO2 quadrupling on plant physiology impact precipitation in three main rainforests. We show that differences between the regions lie in how land‐surface warming (driven by reduced transpiration) interacts with their climatological atmospheric circulations, regardless of their reliance on evapotranspiration. Various atmosphere‐only experiments from two General Circulation Models are used. We find that over New Guinea, land‐surface warming amplifies moisture convergence from the ocean and increases rainfall. In the Congo, no clear rainfall changes emerge as the land‐surface warming effect is offset by migrations of rainfall. In Amazonia, the interaction of land‐surface warming with the climatological circulation pattern leads to a precipitation‐change dipole, with reduced rainfall in central and eastern Amazonia and increased rainfall in the west. Plain Language Summary: Predicting how tropical rainforests will be influenced by climate change is crucial and remains a challenge. We show that precipitation changes over rainforests are predominantly driven by land‐surface warming, caused by reduced transpiration from plants and its interaction with the atmospheric circulation in each region, which explains why each rainforest responds differently. These results rely on model experiments that decompose the complex effects of vegetation changes caused by rising CO2. This study points towards two main ways of reducing uncertainties in future projections: 1) by improving the models' representation of tropical circulation and vegetation and 2) by searching for emergent constraints on rainforest atmospheric circulation and the impact of vegetation changes. Key Points: The three major rainforests respond differently to CO2‐induced plant physiology changesThese differences lie in how the related land‐surface warming interacts with the circulationThey are not driven by differences in evapotranspiration and recycling rate [ABSTRACT FROM AUTHOR]

Aquaplanets with low-heat-capacity slab-ocean boundary conditions can exhibit rapid changes in the regime of the overturning circulation over the seasonal cycle, which have been connected to the onset of Earth's monsoons. In spring, as the ITCZ migrates off the equator, it jumps poleward and a sudden transition occurs from an eddy-driven, equinoctial regime with two weak Hadley cells, to a near-angular-momentum-conserving, solstitial regime with a strong, cross-equatorial winter-hemisphere cell. Here, the controls on the transition latitude and rate are explored in idealized moist aquaplanet simulations. It is found that the transition remains rapid relative to the solar forcing when year length and slab-ocean heat capacity are varied, and, at Earth's rotation rate, always occurs when the ITCZ reaches approximately 7°. This transition latitude is, however, found to scale inversely with rotation rate. Interestingly, the transition rate varies nonmonotonically with rotation, with a maximum at Earth's rotation rate, suggesting that Earth may be particularly disposed to a fast monsoon onset. The fast transition relates to feedbacks in both the atmosphere and the slab ocean. In particular, an evaporative feedback between the lower-level branch of the overturning circulation and the surface temperature is identified. This accelerates monsoon onset and slows withdrawal. Last, comparing eddy-permitting and axisymmetric experiments shows that, in contrast with results from dry models, in this fully moist model the presence of eddies slows the migration of the ITCZ between hemispheres. [ABSTRACT FROM AUTHOR]

There is a growing desire for reliable 21st-century projections of water availability at the regional scale. Global climate models (GCMs) are typically used together with global hydrological models (GHMs) to generate such projections. GCMs alone are unsuitable, especially if they have biased representations of aridity. The Budyko framework represents how water availability varies as a non-linear function of aridity and is used here to constrain projections of runoff from GCMs, without the need for computationally expensive GHMs. Considering a Chinese case study, we first apply the framework to observations to show that the contribution of direct human impacts (water consumption) to the significant decline in Yellow River runoff was greater than the contribution of aridity change by a factor of approximately 2, although we are unable to rule out a significant contribution from the net effect of all other factors. We then show that the Budyko framework can be used to narrow the range of Yellow River runoff projections by 34 %, using a multi-model ensemble and the high-end Representative Concentration Pathway (RCP8.5) emissions scenario. This increases confidence that the Yellow River will see an increase in runoff due to aridity change by the end of the 21st century. Yangtze River runoff projections change little, since aridity biases in GCMs are less substantial. Our approach serves as a quick and inexpensive tool to rapidly update and correct projections from GCMs alone. This could serve as a valuable resource when determining the water management policies required to alleviate water stress for future generations. [ABSTRACT FROM AUTHOR]

There is a growing desire for reliable 21st-century projections of water availability at the regional scale. Global climate models (GCMs) are typically used together with global hydrological models (GHMs) to generate such projections. GCMs alone are unsuitable, especially if they have biased representations of aridity. The Budyko framework describes how water availability varies as a non-linear function of aridity and is used here to constrain projections of runoff from GCMs, without the need for computationally expensive GHMs. Considering a Chinese case study, we first apply the framework to observations to show that the contribution of direct human impacts (water consumption) to the significant decline in Yellow river runoff was greater than the contribution of aridity change by a factor of approximately 2, although we are unable to rule out a significant contribution from the net effect of all other factors. We then show that the Budyko framework can be used to narrow the range of Yellow river runoff projections by 34 %, using a multi-model ensemble and the high end RCP8.5 emissions scenario. This increases confidence that the Yellow river will see an increase in runoff due to aridity change by the end of the 21st century. Yangtze river runoff projections change little, since aridity biases in GCMs are less substantial. Our approach serves as a quick and inexpensive tool to rapidly update and correct projections from GCMs alone. This could serve as a valuable resource when determining the water management policies required to alleviate water stress for future generations. [ABSTRACT FROM AUTHOR]

We present results of simulations of the climate of the newly discovered planet Proxima Centauri B, performed using the Met Office Unified Model (UM). We examine the responses of both an "Earth-like" atmosphere and simplified nitrogen and trace carbon dioxide atmosphere to the radiation likely received by Proxima Centauri B. Additionally, we explore the effects of orbital eccentricity on the planetary conditions using a range of eccentricities guided by the observational constraints. Overall, our results are in agreement with previous studies in suggesting Proxima Centauri B may well have surface temperatures conducive to the presence of liquid water. Moreover, we have expanded the parameter regime over which the planet may support liquid water to higher values of eccentricity (≳ 0:1) and lower incident fluxes (881:7 W m²) than previous work. This increased parameter space arises because of the low sensitivity of the planet to changes in stellar flux, a consequence of the stellar spectrum and orbital configuration. However, we also find interesting differences from previous simulations, such as cooler mean surface temperatures for the tidally-locked case. Finally, we have produced high-resolution planetary emission and reflectance spectra, and highlight signatures of gases vital to the evolution of complex life on Earth (oxygen, ozone and carbon dioxide). [ABSTRACT FROM AUTHOR]