281 research outputs found

    The London, Paris and De Bilt sub‐daily pressure series

    Get PDF
    The construction of sub-daily pressure series is described for the cities of London (GB) and Paris (FR). The series extend back 1692 and 1748, respectively, and as such they represent two of the longest sub-daily series of barometric pressure available. These series are updated from the previously documented London and Paris daily series and offer more homogeneous series, and in the case of the London series a more temporally complete sequence of data. A pairwise homogenization procedure has been applied to the two series alongside the long series of pressure that exists for De Bilt (NL). The De Bilt series has been available for some time in the International Surface Pressure Dataset (ISPD), but further quality control and homogeneity-checking procedures have been applied to the data in this paper and therefore the three series are released together in this dataset. The series are of immediate interest for understanding changes to storm activity across the English Channel and North Atlantic region over an extended timeframe but may also be assimilated into reanalysis datasets such as the 20th-century reanalysis

    AirSeaFluxCode: Open-source software for calculating turbulent air-sea fluxes from meteorological parameters

    Get PDF
    The turbulent exchanges, or fluxes, of heat, moisture and momentum between the atmosphere and the ocean play a crucial role in the Earth’s climate system. Direct measurements of turbulent fluxes are very challenging and sparse, and do not span the full range of environmental conditions that exist over the ocean. This means that empirical “bulk formulae” parameterizations that relate direct flux observations to concurrent measurements of the mean meteorological and sea surface variables contain considerable uncertainty. In this paper, we present a Python 3.6 (or higher) open-source software package “AirSeaFluxCode” for the computation of the heat (latent and sensible) and momentum fluxes. Ten different parameterizations are included, each based on published descriptions or code and each derived from a different set of observations, or different assumptions about the turbulent exchange processes. They represent a range of current expert opinion on how the fluxes depend on mean properties and can be used to explore uncertainty in calculated fluxes. AirSeaFluxCode also allows the adjustment of the mean meteorological input parameters (air temperature, humidity and wind speed) from the height at which they are obtained to a user-defined output height. This height adjustment enables the comparison of measurements, or model-derived values, made at different heights above sea-level. The parameterizations calculate the fluxes using input parameters that are relatively easily to measure, or are available as model output: wind speed, air temperature, sea surface temperature, atmospheric pressure and humidity. Where original code is available we have compared its output with that of AirSeaFluxCode. Any changes made to increase consistency across algorithms by standardizing computational methods or calculation of meteorological variables, for example, are discussed and the impacts quantified: these are shown to be insignificant except for a few cases where conditions were extreme, and AirSeaFluxCode is shown to be robust. We also investigate the impact on the fluxes caused by different assumptions about the exchange processes, or the choices inherent in the implementation of the parameterizations. For example, sea surface temperature usually refers to data typically obtained at depths of between 1 and 10 m. However, since some parameterizations require a “skin” sea surface temperature, code that adjusts temperature at depth to skin temperature is included: this has a very significant impact on the fluxes. Selecting a parameterization that is appropriate for the available sea surface temperature will avoid the need to adjust the sea temperature data and the uncertainties associated with that adjustment, and will also avoid the biases due to use of the “wrong” measure of temperature. Significant differences also resulted from assumptions about the size of reduction in sea surface humidity to account for salinity effects: the uncertainty in the reduction factor needs to be quantified in future analyses. Fluxes in extreme conditions are particularly uncertain since the transfer coefficients in the different parameterizations vary most at very high and very low wind speeds. Low wind speeds are also challenging for numerical implementation since choices have to be made regarding: convergence criteria for the iterative calculation, inclusion of a parameterization for convective gustiness, or application of ad hoc limits to various parameters. All of these choices can significantly affect the flux estimates for light winds

    Finale: Impact of the ORCHESTRA/ENCORE programmes on Southern Ocean heat and carbon understanding

    Get PDF
    The 5-year Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA) programme and its 1-year extension ENCORE (ENCORE is the National Capability ORCHESTRA Extension) was an approximately 11-million-pound programme involving seven UK research centres that finished in March 2022. The project sought to radically improve our ability to measure, understand and predict the exchange, storage and export of heat and carbon by the Southern Ocean. It achieved this through a series of milestone observational campaigns in combination with model development and analysis. Twelve cruises in the Weddell Sea and South Atlantic were undertaken, along with mooring, glider and profiler deployments and aircraft missions, all contributing to measurements of internal ocean and air–sea heat and carbon fluxes. Numerous forward and adjoint numerical experiments were developed and supported by the analysis of coupled climate models. The programme has resulted in over 100 peer-reviewed publications to date as well as significant impacts on climate assessments and policy and science coordination groups. Here, we summarize the research highlights of the programme and assess the progress achieved by ORCHESTRA/ENCORE and the questions it raises for the future. This article is part of a discussion meeting issue ‘Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities’

    Quantifying daytime heating biases in marine air temperature observations from ships

    No full text
    Marine air temperatures recorded on ships during the daytime are known to be biased warm on average due to energy storage by the superstructure of the vessels. This makes unadjusted daytime observations unsuitable for many applications including for the monitoring of long-term temperature change over the oceans. In this paper a physics-based approach is used to estimate this heating bias in ship observations from ICOADS. Under this approach, empirically determined coefficients represent the energy transfer terms of a heat budget model which quantifies the heating bias and is applied as a function of cloud cover and the relative wind speed over individual ships. The coefficients for each ship are derived from the anomalous diurnal heating relative to nighttime air temperature. Model coefficients, cloud cover and relative wind speed are then used to estimate the heating bias ship-by-ship and generate nighttime-equivalent time series. A variety of methodological approaches were tested. Application of this method enables the inclusion of some daytime observations in climate records based on marine air temperatures, allowing an earlier start date and giving an increase in spatial coverage compared to existing records that exclude daytime observations

    Global Climate

    Get PDF
    In 2021, both social and economic activities began to return towards the levels preceding the COVID-19 pandemic for some parts of the globe, with others still experiencing restrictions. Meanwhile, the climate has continued to respond to the ongoing increase in greenhouse gases and resulting warming. La Niña, a phenomenon which tends to depress global temperatures while changing rainfall patterns in many regions, prevailed for all but two months of the year. Despite this, 2021 was one of the six-warmest years on record as measured by global mean surface temperature with an anomaly of between +0.21° and +0.28°C above the 1991–2020 climatology. Lake surface temperatures were their highest on record during 2021. The number of warm days over land also reached a new record high. Exceptional heat waves struck the Pacific Coast of North America, leading to a new Canadian maximum temperature of 49.6°C at Lytton, British Columbia, on 29 June, breaking the previous national record by over 4°C. In Death Valley, California, the peak temperature reached 54.4°C on 9 July, equaling the temperature measured in 2020, and the highest temperature recorded anywhere on the globe since at least the 1930s. Over the Mediterranean, a provisional new European record of 48.8°C was set in Sicily on 11 August. In the atmosphere, the annual mean tropospheric temperature was among the 10 highest on record, while the stratosphere continued to cool. While La Niña was present except for June and July, likely influencing Australia’s coolest year since 2012 and wettest since 2016, other modes of variability played important roles. A negative Indian Ocean dipole event became established during July, associated with a warmer east and cooler west Indian Ocean. Northern Hemisphere winters were affected by a negative phase of the North Atlantic Oscillation at both the beginning and end of 2021. In the Southern Hemisphere, a very strong positive Southern Annular Mode (also known as the Antarctic Oscillation) contributed to New Zealand’s record warm year and to very cold temperatures over Antarctica. Land surface winds continued a slow reversal from the multi-decadal stilling, and over the ocean wind speeds were at their highest in almost a decade. La Niña conditions had a clear influence on the regional patterns of many hydrological variables. Surface specific humidity and total column water vapor over land and ocean were higher than average in almost all datasets. Relative humidity over land reached record or near-record low saturation depending on the dataset, but with mixed signals over the ocean. Satellite measurements showed that 2021 was the third cloudiest in the 19-year record. The story for precipitation was mixed, with just below-average mean precipitation falling over land and below-average mean precipitation falling over the ocean, while extreme precipitation was generally more frequent, but less intense, than average. Differences between means and extremes can be due to several factors, including using different indices, observing periods, climatological base reference periods, and levels of spatial completeness. The sharp increase in global drought area that began in mid-2019 continued in 2021, reaching a peak in August with 32% of global land area experiencing moderate or worse drought, and declining slightly thereafter. Arctic permafrost temperatures continued to rise, reaching record values at many sites, and the thickness of the layer which seasonally thaws and freezes also increased over 2020 values in a number of regions. It was the 34th-consecutive year of mass balance loss for alpine glaciers in mountainous regions, with glaciers on average 25 m thinner than in the late 1970s. And the duration of lake ice in the Northern Hemisphere was the fourth lowest in situ record dating back to 1991. The atmospheric concentrations of the major long-lived greenhouse gases, CO2, CH4, and N2O, all reached levels not seen in at least the last million years and grew at near-record rates in 2021. La Niña conditions did not appear to have any appreciable impact on their growth rates. The growth rate for CH4, of 17 ppb yr−1, was similar to that for 2020 and set yet another record, although the causes for this post-2019 acceleration are unknown presently. Overall, CO2 growth continues to dominate the increase in global radiative forcing, which increased from 3.19 to 3.23 W m−2 (watts per square meter) during the year. In 2021, stratospheric ozone did not exhibit large negative anomalies, especially near the poles, unlike 2020, where large ozone depletions appeared, mainly from dynamical effects. The positive impact of reductions in emissions of ozone depleting substances can be seen most clearly in the upper stratosphere, where such dynamical effects are less pronounced. It was the fourth-lowest fire year since global records began in 2003, though extreme regional fire activity was again seen in North America and also in Siberia; as in 2020, the effects of wildfires in these two regions led to locally large regional positive anomalies in tropospheric aerosol and carbon monoxide abundance. Vegetation is responding to the higher global mean temperatures, with the satellite-derived measures for the Northern Hemisphere for 2021 rated among the earliest starts of the growing season and the latest end of the season on record. The first bloom date for cherry trees in Kyoto, Japan, broke a 600-year record set in 1409. This year we welcome a sidebar on the global distribution of lightning, which has been recently declared an essential climate variable (ECV) by the Global Climate Observing System (GCOS). Time series and anomaly maps from many of the variables described in this chapter can be found in Plates 1.1 and 2.1. As with other chapters, many of the sections have moved from the previous 1981–2010 to the new 1991–2020 climatological reference period, in line with WMO recommendations (see Chapter 1). This is not possible for all datasets, as it is dependent on their length of record or legacy processing methods. While anomalies from the new climatology period are not so easily comparable with previous editions of this report, they more clearly highlight deviations from more recent conditions

    Extended north Atlantic oscillation and Greenland blocking indices 1800–2020 from new meteorological reanalysis

    Get PDF
    Based on newly-available meteorological reanalysis, we compile and present extended seasonal series of the North Atlantic Oscillation (NAO) and Greenland Blocking indices spanning 1800–2020, which we analyse for evidence of significant trends. This represents a major backward extension of the previously available instrumental-/reanalysis-based Azores–Iceland and principal component-based NAO indices, and allows us to evaluate the potential effect of natural climate perturbations, especially the 1809 and 1815 major volcanic eruptions and ~1790s–1830 Dalton solar minimum, on North Atlantic atmospheric circulation. We find that winters 1809/10 and 1816/17 mark positive NAO peaks, relative to several years before and afterwards, which is in accordance with the theory of volcanic forcing of climate. However, there is little evidence of a summer NAO volcanic signature. Overall, based on the significantly longer new reanalysis time series, the new series presented here corroborate and extend our previous results of: (1) a significantly more variable year-to-year NAO with a recent exceptional clustering of extreme events since 2000 for winter; (2) a significant increasing trend in blocking over Greenland in summer. These trends have major repercussions for the probability of the occurrence of extreme weather events over northwest Europe and for the sensitivity and response of the Greenland Ice Sheet to global warming, especially if they continue as an integral part of anthropogenic climate chang

    The economic case for hospital discharge services for people experiencing homelessness in England

    Get PDF
    There are long-standing concerns that people experiencing homelessness may not recover well if left unsupported after a hospital stay. This paper reports on a study investigating the costeffectiveness of three different ‘in patient care coordination and discharge planning’ configurations for adults experiencing homelessness who are discharged from hospitals in England. The first configuration provided a clinical and housing in-reach service during acute care and discharge coordination but with no ‘step-down’ care. The second configuration provided clinical and housing in-reach, discharge coordination and ‘step-down’ intermediate care. The third configuration consisted of housing support workers providing in-reach and discharge coordination as well as step-down care. These three configurations were each compared with ‘standard care’ (control, defined as one visit by the homelessness health nurse before discharge during which patients received an information leaflet on local services). Multiple sources of data and multi-outcome measures were adopted to assess the cost-utility of hospital discharge service delivery for the NHS and broader public perspective. Details of 354 participants were collated on service delivery costs (salary, on-costs, capital, overheads and ‘hotel’ costs, advertising and other indirect costs), the economic consequences for different public services (e.g. NHS, social care, criminal justice, housing, etc), and health utilities (qualityadjusted-life-years, QALYs). Findings were complex across the configurations, but, on the whole, there was promising evidence suggesting that, with delivery costs similar to those reported for bed-based intermediate care, step-down care secured better health outcomes and 4 improved cost-effectiveness (compared with usual care) within NICE cost-effectiveness recommendations

    Homelessness and integrated care: an application of integrated care knowledge to understanding services for wicked issues

    Get PDF
    Purpose: People experiencing homelessness often have complex needs requiring a range of support. These may include health problems (physical illness, mental health and/or substance misuse) as well as social, financial and housing needs. Addressing these issues requires a high degree of coordination amongst services. It is, thus, an example of a wicked policy issue. The purpose of this paper is to examine the challenge of integrating care in this context using evidence from an evaluation of English hospital discharge services for people experiencing homelessness. Design/methodology/approach: The paper undertakes secondary analysis of qualitative data from a mixed methods evaluation of hospital discharge schemes and uses an established framework for understanding integrated care, the Rainbow Model of Integrated Care (RMIC), to help examine the complexities of integration in this area. Findings: Supporting people experiencing homelessness to have a good discharge from hospital was confirmed as a wicked policy issue. The RMIC provided a strong framework for exploring the concept of integration, demonstrating how intertwined the elements of the framework are and, hence, that solutions need to be holistically organised across the RMIC. Limitations to integration were also highlighted, such as shortages of suitable accommodation and the impacts of policies in aligned areas of the welfare state. Research limitations/implications: The data for this secondary analysis were not specifically focussed on integration which meant the themes in the RMIC could not be explored directly nor in as much depth. However, important issues raised in the data directly related to integration of support, and the RMIC emerged as a helpful organising framework for understanding integration in this wicked policy context. Practical implications: Integration is happening in services directly concerned with the discharge from hospital of people experiencing homelessness. Key challenges to this integration are reported in terms of the RMIC, which would be a helpful framework for planning better integrated care for this area of practice. Social implications: Addressing homelessness not only requires careful planning of integration of services at specific pathway points, such as hospital discharge, but also integration across wider systems. A complex set of challenges are discussed to help with planning the better integration desired, and the RMIC was seen as a helpful framework for thinking about key issues and their interactions. Originality/value: This paper examines an application of integrated care knowledge to a key complex, or wicked policy issue