129 research outputs found
Can models robustly represent aerosol–convection interactions if their cloud microphysics is uncertain?
This study investigates the hydrometeor development and response to cloud droplet number concentration (CDNC) perturbations in convection-permitting model configurations. We present results from a real-data simulation of deep convection in the Congo basin, an idealised supercell case, and a warm-rain large-eddy simulation (LES). In each case we compare two frequently used double-moment bulk microphysics schemes and investigate the response to CDNC perturbations. In the Congo basin simulations both microphysics schemes have large positive biases in surface precipitation, frequency of high radar reflectivities and frequency of cold cloud compared to observations. In all cases, differences in the simulated cloud morphology and precipitation are found to be significantly greater between the microphysics schemes than due to CDNC perturbations within each scheme. Further, we show that the response of the hydrometeors to CDNC perturbations strongly differs not just between microphysics schemes but also between different cases of convection. Sensitivity tests show that the representation of autoconversion is the dominant factor that drives differences in rain production between the microphysics schemes in the idealised precipitating shallow cumulus case and in a sub-region of the Congo basin simulations dominated by liquid-phase processes. In this region, rain mass is also shown to be relatively insensitive to the radiative effects of an overlying layer of ice-phase cloud. In the idealised supercell case, thermodynamic impacts on the storm system using different microphysics parameterisations can equal those due to aerosol effects. These results highlight the large uncertainty in cloud and precipitation responses to aerosol in convection-permitting simulations and have important implications not just for modelling studies of aerosol-convection interaction. These results indicate the continuing need for tighter observational constraints of cloud processes and response to aerosol in a range of meteorological regimes
Maternal deaths in Pakistan : intersection of gender, class and social exclusion.
Background: A key aim of countries with high maternal mortality rates is to increase availability of competent
maternal health care during pregnancy and childbirth. Yet, despite significant investment, countries with the
highest burdens have not reduced their rates to the expected levels. We argue, taking Pakistan as a case study,
that improving physical availability of services is necessary but not sufficient for reducing maternal mortality
because gender inequities interact with caste and poverty to socially exclude certain groups of women from
health services that are otherwise physically available.
Methods: Using a critical ethnographic approach, two case studies of women who died during childbirth were
pieced together from information gathered during the first six months of fieldwork in a village in Northern Punjab,
Pakistan.
Findings: Shida did not receive the necessary medical care because her heavily indebted family could not afford it.
Zainab, a victim of domestic violence, did not receive any medical care because her martial family could not afford
it, nor did they think she deserved it. Both women belonged to lower caste households, which are materially poor
households and socially constructed as inferior.
Conclusions: The stories of Shida and Zainab illustrate how a rigidly structured caste hierarchy, the gendered
devaluing of females, and the reinforced lack of control that many impoverished women experience conspire to
keep women from lifesaving health services that are physically available and should be at their disposal
Challenges in constraining anthropogenic aerosol effects on cloud radiative forcing using present-day spatiotemporal variability
This is the final version. Available from National Academy of Sciences via the DOI in this recordA large number of processes are involved in the chain from emissions of aerosol precursor gases and primary particles to impacts on cloud radiative forcing. Those processes are manifest in a number of relationships that can be expressed as factors dlnX/dlnY driving aerosol effects on cloud radiative forcing. These factors include the relationships between cloud condensation nuclei (CCN) concentration and emissions, droplet number and CCN concentration, cloud fraction and droplet number, cloud optical depth and droplet number, and cloud radiative forcing and cloud optical depth. The relationship between cloud optical depth and droplet number can be further decomposed into the sum of two terms involving the relationship of droplet effective radius and cloud liquid water path with droplet number. These relationships can be constrained using observations of recent spatial and temporal variability of these quantities. However, we are most interested in the radiative forcing since the preindustrial era. Because few relevant measurements are available from that era, relationships from recent variability have been assumed to be applicable to the preindustrial to present-day change. Our analysis of Aerosol Comparisons between Observations and Models (AeroCom) model simulations suggests that estimates of relationships from recent variability are poor constraints on relationships from anthropogenic change for some terms, with even the sign of some relationships differing in many regions. Proxies connecting recent spatial/temporal variability to anthropogenic change, or sustained measurements in regions where emissions have changed, are needed to constrain estimates of anthropogenic aerosol impacts on cloud radiative forcing.The Pacific Northwest National Laboratory (PNNL) is operated for the Department of Energy (DOE) by Battelle Memorial Institute under Contract DE-AC06-76RLO 1830. Work at PNNL was supported by the US DOE Decadal and Regional Climate Prediction using Earth System Models program and by the US DOE Earth System Modeling program. Work of M.W. and S.Z. performed at Nanjing University was supported by the One Thousand Young Talent Program, Jiangsu Province Specially-Appointed Professor Grant, and the National Natural Science Foundation of China (41575073). A portion of this research was performed using PNNL Institutional Computing resources. The ECHAM6-HAM model was developed by a consortium composed of ETH Zurich, Max Planck Institut für Meteorologie, Forschungszentrum Jülich, University of Oxford, the Finnish Meteorological Institute, and the Leibniz Institute for Tropospheric Research, and is managed by the Center for Climate Systems Modeling (C2SM) at ETH Zurich. D.N. acknowledges support by the Austrian Science Fund (J 3402-N29, Erwin Schrödinger Fellowship Abroad). C2SM at ETH Zurich is acknowledged for providing technical and scientific support. This work was also supported by a grant from the Swiss National Supercomputing Centre under Project ID s431. D.G.P. and P.S. acknowledge support from the United Kingdom (UK) Natural Environment Research Council Grant NE/I020148/1. P.S. and Z.K. acknowledge funding from the European Research Council (ERC) under the European Union’s Seventh Framework Programme (FP7/2007–2013) ERC project ACCLAIM (Grant Agreement FP7-280025). The development of modal version of the GLObal Model of Aerosol Processes (GLOMAP-mode) within Hadley Center Global Environmental Mode (HadGEM) is part of the United Kingdom Chemistry and Aerosols (UKCA) project, which is supported by both National Environmental Research Council (NERC) and the Joint Department of Energy & Climate Change/Department for Environment, Food & Rural Affairs Meteorology Office Hadley Centre Climate Programme. We acknowledge use of the Met Office and NERC MONSooN high performance computing system, a collaborative facility supplied under the Joint Weather and Climate Research Programme, a strategic partnership between the Met Office and the NERC. Simulations by SPRINTARS were executed with the supercomputer system SX-9/ACE of the National Institute for Environmental Studies, Japan. SPRINTARS is partly supported by the Environment Research and Technology Development Fund (S-12-3) of the Ministry of the Environment, Japan and Japan Society for the Promotion of Science KAKENHI Grants-in-Aid for Scientific Research 15H01728 and 15K12190. Computing resources for CAM5-MG2 simulations were provided by the Climate Simulation Laboratory at National Center for Atmospheric Research (NCAR) Computational and Information Systems Laboratory. NCAR is sponsored by the US National Science Foundation
On the characteristics of aerosol indirect effect based on dynamic regimes in global climate models
This is the final version of the article. Available from EGU via the DOI in this record.Aerosol–cloud interactions continue to constitute a major source of uncertainty for the estimate of climate radiative forcing. The variation of aerosol indirect effects (AIE) in climate models is investigated across different dynamical regimes, determined by monthly mean 500 hPa vertical pressure velocity (ω500), lower-tropospheric stability (LTS) and large-scale surface precipitation rate derived from several global climate models (GCMs), with a focus on liquid water path (LWP) response to cloud condensation nuclei (CCN) concentrations. The LWP sensitivity to aerosol perturbation within dynamic regimes is found to exhibit a large spread among these GCMs. It is in regimes of strong large-scale ascent (ω500 0.1 mm day−1) contributes the most to the total aerosol indirect forcing (from 64 to nearly 100 %). Results show that the uncertainty in AIE is even larger within specific dynamical regimes compared to the uncertainty in its global mean values, pointing to the need to reduce the uncertainty in AIE in different dynamical regimes.M. Wang acknowledged the support from
the Jiangsu Province Specially-appointed professorship grant
and the One Thousand Young Talents Program and the National
Natural Science Foundation of China (41575073). The contribution
from Pacific Northwest National Laboratory was supported by
the US Department of Energy (DOE), Office of Science, Decadal
and Regional Climate Prediction using Earth System Models
(EaSM program). H. Wang acknowledges support by the DOE
Earth System Modeling program. The Pacific Northwest National
Laboratory is operated for the DOE by Battelle Memorial Institute
under contract DE-AC06-76RLO 1830. The ECHAM-HAMMOZ
model is developed by a consortium composed of ETH Zurich,
Max Planck Institut für Meteorologie, Forschungszentrum Jülich,
University of Oxford, the Finnish Meteorological Institute and
the Leibniz Institute for Tropospheric Research, and managed
by the Center for Climate Systems Modeling (C2SM) at ETH
Zurich. D. Neubauer gratefully acknowledges the support by the
Austrian Science Fund (FWF): J 3402-N29 (Erwin Schrödinger
Fellowship Abroad). The Center for Climate Systems Modeling
(C2SM) at ETH Zurich is acknowledged for providing technical
and scientific support. This work was supported by a grant from
the Swiss National Supercomputing Centre (CSCS) under project
ID s431. D. G. Partridge would like to acknowledge support
from the UK Natural Environment Research Council project
ACID-PRUF (NE/I020148/1) as well as thanks to N. Bellouin for
useful discussions during the course of this work. The development
of GLOMAP-mode within HadGEM is part of the UKCA project,
which is supported by both NERC and the Joint DECC/Defra
Met Office Hadley Centre Climate Programme (GA01101).
We acknowledge use of the MONSooN system, a collaborative
facility supplied under the Joint Weather and Climate Research
Programme, a strategic partnership between the Met Office and
the Natural Environment Research Council. P. Stier would like
to acknowledge support from the European Research Council
under the European Union’s Seventh Framework Programme
(FP7/2007-2013) / ERC grant agreement no. FP7-280025
Recommended from our members
Ensembles of global climate model variants designed for the quantification and constraint of uncertainty in aerosols and their radiative forcing
Tropospheric aerosol radiative forcing has persisted for many years as one of the major causes of uncertainty in global climate model simulations. To sample the range of plausible aerosol and atmospheric states and perform robust statistical analyses of the radiative forcing, it is important to account for the combined effects of many sources of model uncertainty, which is rarely done due to the high computational cost. This paper describes the designs of two ensembles of the HadGEM-UKCA global climate model and provides the first analyses of the uncertainties in aerosol radiative forcing and their causes. The first ensemble was designed to comprehensively sample uncertainty in the aerosol state, while the other samples additional uncertainties in the physical model related to clouds, humidity and radiation, thereby allowing an analysis of uncertainty in the aerosol effective radiative forcing. Each ensemble consists of around 200 simulations of the pre-industrial and present-day atmospheres. The uncertainty in aerosol radiative forcing in our ensembles is comparable to the range of estimates from multi-model intercomparison projects. The mean aerosol effective radiative forcing is –1.45 W m–2 (credible interval –2.07 to –0.81 W m–2), which encompasses but is more negative than the –1.17 W m–2 in
the 2013 Atmospheric Chemistry and Climate Model Intercomparison Project and –0.90 W m–2 in the IPCC 5th Assessment Report. The ensembles can be used to reduce aerosol radiative forcing uncertainty by challenging them with multiple measurements as well as to isolate potential causes of multi-model differences
Impact of assimilating NOAA VIIRS aerosol optical depth (AOD) observations on global AOD analysis from the Copernicus Atmosphere Monitoring Service (CAMS)
Global monitoring of aerosols is required to analyse the impacts of aerosols on air quality and to understand their role in modulating the climate variability. The Copernicus Atmosphere Monitoring Service (CAMS) provides near-real-time forecasts and reanalyses of aerosols using the ECMWF Integrated Forecasting System (IFS), constrained by the assimilation of MODIS and Polar Multi-Sensor Aerosol Optical Properties (PMAp) aerosol optical depth (AOD). Given the potential
end of lifetime of MODIS AOD, implementing new AOD observations in the CAMS operational suite is a priority to ensure the continuity of the CAMS
forecast performances. The objective of this work is to test the assimilation of the NOAA VIIRS AOD product from S-NPP and NOAA20 satellites in the
IFS model. Simulation experiments assimilating VIIRS on top or in place of MODIS were carried out from June 2021 to November 2021 to evaluate the
impacts on the AOD analysis.
For maritime aerosol background, the assimilation of VIIRS and the use of VIIRS from NOAA20 as an anchor reduce the analysis AOD values compared to
MODIS-based experiments, in which the analysis values were too high due to the positive bias of MODIS/Terra over ocean. Over land, the assimilation
of VIIRS induces a large increase in the analysis over biomass burning regions where VIIRS shows larger AOD than MODIS due to differences in the
aerosol models and cloud filtering between MODIS and VIIRS retrieval algorithms. For dust source regions, the analysis is reduced when VIIRS is
assimilated on top of or in place of MODIS, particularly over the Sahara, the Arabian Peninsula and a few places in Asia in the July–August period. The
assimilation of VIIRS leads to an overall reduction of the bias in AOD analysis evaluated against AERONET measurements, with the largest bias
reduction over Europe and desert and maritime sites.</p
Investigation of the Origin and Spread of a Mammalian Transposable Element Based on Current Sequence Diversity
Almost half the human genome consists of mobile DNA elements, and their analysis is a vital part of understanding the human genome as a whole. Many of these elements are ancient and have persisted in the genome for tens or hundreds of millions of years, providing a window into the evolution of modern mammals. The Golem family have been used as model transposons to highlight computational analyses which can be used to investigate these elements, particularly the use of molecular dating with large transposon families. Whole-genome searches found Golem sequences in 20 mammalian species. Golem A and B subsequences were only found in primates and squirrel. Interestingly, the full-length Golem, found as a few copies in many mammalian genomes, was found abundantly in horse. A phylogenetic profile suggested that Golem originated after the eutherian–metatherian divergence and that the A and B subfamilies originated at a much later date. Molecular dating based on sequence diversity suggests an early age, of 175 Mya, for the origin of the family and that the A and B lineages originated much earlier than expected from their current taxonomic distribution and have subsequently been lost in some lineages. Using publically available data, it is possible to investigate the evolutionary history of transposon families. Determining in which organisms a transposon can be found is often used to date the origin and expansion of the families. However, in this analysis, molecular dating, commonly used for determining the age of gene sequences, has been used, reducing the likelihood of errors from deleted lineages
Addressing disparities in maternal health care in Pakistan: gender, class and exclusion
Background: After more than two decades of the Safe Motherhood Initiative and Millennium Development Goals aimed at reducing maternal mortality, women continue to die in childbirth at unacceptably high rates in Pakistan. While an extensive literature describes various programmatic strategies, it neglects the rigorous analysis of the reasons these strategies have been unsuccessful, especially for women living at the economic and social margins of society. A critical gap in current knowledge is a detailed understanding of the root causes of disparities in maternal health care, and in particular, how gender and class influence policy formulation and the design and delivery of maternal health care services. Taking Pakistan as a case study, this research builds upon two distinct yet interlinked conceptual approaches to understanding the phenomenon of inequity in access to maternal health care: social exclusion and health systems as social institutions.
Methods/Design: This four year project consists of two interrelated modules that focus on two distinct groups of participants: (1) poor, disadvantaged women and men and (2) policy makers, program managers and health service providers. Module one will employ critical ethnography to understand the key axes of social exclusion as related to gender, class and zaat and how they affect women’s experiences of using maternal health care. Through health care setting observations, interviews and document review, Module two will assess policy design and delivery of maternal health services.
Discussion: This research will provide theoretical advances to enhance understanding of the power dynamics of gender and class that may underlie poor women’s marginalization from health care systems in Pakistan. It will also provide empirical evidence to support formulation of maternal health care policies and health care system practices aimed at reducing disparities in maternal health care in Pakistan. Lastly, it will enhance inter-disciplinary research capacity in the emerging field of social exclusion and maternal health and help reduce social inequities and achieve the Millennium Development Goal No. 5
An evidence-based review of creative problem solving tools: a practitioner’s resource
Creative problem solving (CPS) requires solutions to be useful and original. Typically, its operations span problem finding, idea generation and critical evaluation. The benefits of training CPS have been extolled in education, industry and government with evidence showing it can enhance performance. However, while such training schemes work, less is known about the specific tools used. Knowing whether a particular tool works or not would provide practitioners with a valuable resource, leading to more effective training schemes, and a better understanding of the processes involved. A comprehensive review was undertaken examining the empirical support of tools used within CPS. Despite the surprising lack of research focusing on the use and success of specific tools some evidence exists to support the effectiveness of a small set. Such findings present practitioners with a potential resource that could be used in a stand-alone setting or possibly combined to create more effective training programmes
Lineage-Specific Biology Revealed by a Finished Genome Assembly of the Mouse
A finished clone-based assembly of the mouse genome reveals extensive recent sequence duplication during recent evolution and rodent-specific expansion of certain gene families. Newly assembled duplications contain protein-coding genes that are mostly involved in reproductive function
- …