Wind Speed Influences on Marine Aerosol Optical Depth

The Mulcahy (Mulcahy et al., 2008) power-law parameterization, derived at the coastal Atlantic station Mace Head, between clean marine aerosol optical depth (AOD) and wind speed is compared to open ocean MODIS-derived AOD versus wind speed. The reported AOD versus wind speed (U) was a function of ∼U2. The open ocean MODIS-derived AOD at 550 nm and 860 nm wavelengths, while in good agreement with the general magnitude of the Mulcahy parameterization, follows a power-law with the exponent ranging from 0.72 to 2.47 for a wind speed range of 2–18 m s−1. For the four cases examined, some MODIS cases underestimated AOD while other cases overestimated AOD relative to the Mulcahy scheme. Overall, the results from MODIS support the general power-law relationship of Mulcahy, although some linear cases were also encountered in the MODIS dataset. Deviations also arise between MODIS and Mulcahy at higher wind speeds (>15 m s−1), where MODIS-derived AOD returns lower values as compared to Mulcahy. The results also support the suggestion than wind generated sea spray, under moderately high winds, can rival anthropogenic pollution plumes advecting out into marine environments with wind driven AOD contributing to AOD values approaching 0.3

The influence of remote aerosol forcing from industrialised economies on the future evolution of East and West African rainfall

Past changes in global industrial aerosol emissions have played a significant role in historical shifts in African rainfall and yet assessment of the impact on African rainfall of near term (10-40 year) potential aerosol emission pathways remains largely unexplored. Whilst existing literature links future aerosol declines to a northward shift of Sahel rainfall, existing climate projections rely on RCP scenarios that do not explore the range of air quality drivers. Here we present projections from two emission scenarios that better envelope the range of potential aerosol emissions. More aggressive emission cuts results in northward shifts of the tropical rain-bands whose signal can emerge from expected internal variability on short, 10-20 year, time horizons. We also show for the first time that this northward shift also impacts East Africa, with evidence of delays to both onset and withdrawal of the Short Rains. However, comparisons of rainfall impacts across models suggest that only certain aspects of both the West and East African model responses may be robust, given model uncertainties. This work motivates the need for wider exploration of air quality scenarios in the climate science community to assess the robustness of these projected changes and to provide evidence to underpin climate adaptation in Africa. In particular, revised estimates of emission impacts of legislated measures every 5-10 years would have a value in providing near term climate adaptation information for African stakeholders

Putting climate resilience in its place: developing spatially literate climate adaptation initiatives

Understanding the socioeconomic, cultural, historical and political nuances of a place is essential for realising effective local decision-making for climate action. People are central to understanding place-based risk and resilience, with consideration of inequality and vulnerability required for effective place-based climate adaptation. Temporality is important. Place is not fixed, but changes over time, together with the community that inhabits it. Discussing and sharing community knowledge increases the likelihood of successful creation and implementation of climate adaptation practices. A sense of place can be deployed to build connections between people, across policy and between scales

Plate-based diversity subset screening generation 2: An improved paradigm for high throughput screening of large compound files

High throughput screening (HTS) is an effective method for lead and probe discovery that is widely used in industry and academia to identify novel chemical matter and to initiate the drug discovery process. However, HTS can be time-consuming and costly and the use of subsets as an efficient alternative to screening these large collections has been investigated. Subsets may be selected on the basis of chemical diversity, molecular properties, biological activity diversity, or biological target focus. Previously we described a novel form of subset screening: plate-based diversity subset (PBDS) screening, in which the screening subset is constructed by plate selection (rather than individual compound cherry-picking), using algorithms that select for compound quality and chemical diversity on a plate basis. In this paper, we describe a second generation approach to the construction of an updated subset: PBDS2, using both plate and individual compound selection, that has an improved coverage of the chemical space of the screening file, whilst only selecting the same number of plates for screening. We describe the validation of PBDS2 and its successful use in hit and lead discovery. PBDS2 screening became the default mode of singleton (one compound per well) HTS for lead discovery in Pfizer

Psychosocial factors in postpartum depression

This study examined 214 New Zealand women, both during pregnancy and in the postpartum, in order to determine the influence of infant-related stressors, unplanned pregnancy, social support and the role of the marital relationship in the development of postpartum depression. The relationship of demographic factors, the woman's feelings about having a new baby in the family and previous history of depression were also analyzed. The prevalence of depressive symptomatology was 30.8% during pregnancy and 39.7% in the postpartum. Postpartum depression was predicted by depression during pregnancy, by poorer postpartum marital adjustment and by lower levels of postpartum social support. The strongest predictor of the change in depression scores over time was depression during pregnancy. The important role of depression during pregnancy in the etiology of postpartum depression, suggests that postpartum depression is a continuation of depression during pregnancy. Women who were more depressed during pregnancy tended to be younger, of lower socio-economic status, and to have a reported history of depressive episodes prior to their pregnancies. Higher levels of prepartum depression were also related to women's feelings of being unhappier about having a new baby in the family, to poorer marital adjustment, and to lower levels of social support during pregnancy. Depression during pregnancy was found to be more likely to have a negative effect on marital adjustment than poor marital adjustment on depression. Similarly, depression during pregnancy was found to be more likely to have a negative effect on social support, than vice versa. However, further regression analyses, showed that postpartum marital adjustment and postpartum social support had a strong relation to postpartum depression, irrespective of the levels of prepartum marital adjustment, prepartum social support, and prepartum depression. Contrary to predictions, neither infant temperament, nor infant risk were related to postpartum depression

Global and local ozone measurements from the thermal infrared IASI/METOP sounder

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What can climate services learn from theory and practice of co-production?

Co-produced climate services are increasingly recognised as a means of improving the effective generation and utilisation of climate information to inform decision-making and support adaptation to climate change, particularly in developing countries. There is a rich literature outlining the theoretical and conceptual evolution of co-production, and experiences of it in a variety of decision contexts – in different sectors and at different scales. However, the extent to which the producers of climate services have engaged with this literature varies. Reflecting the emerging interest and application, particularly in developing countries, this paper reviews the co-production literature to distil some key principles to inform climate services. Whilst we aim to be neither comprehensive nor prescriptive, these principles can inform a normative and pragmatic approach to co-produced climate services. A co-produced climate service product should be decision-driven, process-based and time-managed. The process of co-producing a climate service should be inclusive, collaborative and flexible. Illustrations are also provided of how these principles may be engaged in practice. Evaluation of these emerging examples will help further inform co-production of climate services. Keywords: Co-production, Climate services, Developing countries, Science-society relations, Post-normal science, Producer-user relation

Uncertainties in the determination of the organic fraction of global sea-spray emissions

International audienceSea-spray aerosol considerably affects the climate, both directly and indirectly. The emission rate of sea-spray droplets per unit area of the sea surface is implemented in climate models through a sea-spray source function. The uncertainty between existing formulations of the sea-spray source function that is parameterized in terms of wind speed and sea surface temperature is more than a factor of 2. Organic material substantially contributes to the composition of sea-spray aerosols, especially in biological active regions. Small sea-spray particles may be mainly composed of organic carbon with a decreasing contribution as particle size increases. The sizes in which organic carbon occurs are in the active CCN range and a change in composition may thus have a substantial effect on cloud droplet formation. A first attempt to include the OC fraction of sea-spray in a sea-spray source function was presented by O'Dowd et al. (2008). These authors proposed to use remotely sensed chlorophyll concentration data as a proxy for oceanic biological activity. An organics-chlorophyll relationship was determined by correlating chlorophyll satellite data and in-situ measurements of water insoluble organic compounds. This information was used together with the sea-spray source function to determine the surface flux of the combined inorganic/organic sea-spray particles (O'Dowd et al., 2008; Vignati et al., 2009; Albert et al., 2010). By introducing this methodology one inevitably introduces uncertainties due to the choice of a certain satellite instrument to obtain the chlorophyll data and the choice of the resolution and compositing period of the data. Other uncertainties that are introduced are due to the handling of the satellite data and the fit that is used in the organics-chlorophyll correlation. The organic fraction estimate can additionally be affected by the time period that is studied and the source function that is used to calculate the total sea-spray emission. We will first present a basis methodology to estimate the global emission of the submicron organic matter fraction of sea-spray. Starting from a first estimate of the annual global emission we have performed a sensitivity analysis regarding the above mentioned uncertainties. We found differences of up to at least 50% depending on the chosen parameterizations. Especially the choice of different source functions and the fit that was used in the organics-chlorophyll correlation were found to cause large deviations from our first estimate. From this we can conclude that the estimation of the fraction of organic matter in submicron sea-spray aerosol is still very uncertain. REFERENCES Albert, M.F.M.A., M. Schaap, G. de Leeuwand P.J.H. Builtjes (2010). Progress in the determination of the sea spray source function from satellite data. Journal of Integrative Environmental Sciences, accepted. O'Dowd, C.D. et al., 2008. A combined organic-inorganic sea-spray source function. Geophysical Research Letters, 35(L01801). Vignati E, Facchini MC, Rinaldi M, Scannell C, Ceburnis D, Sciare J, Kanakidou M, Myriokefalitakis S, Dentener F and O'Dowd CD. 2009. Global scale emission and distribution of sea spray aerosol: sea-salt and organic enrichment. Atmospheric Environment, accepted

Uncertainties in the determination of the organic fraction of global sea-spray emissions

International audienceSea-spray aerosol considerably affects the climate, both directly and indirectly. The emission rate of sea-spray droplets per unit area of the sea surface is implemented in climate models through a sea-spray source function. The uncertainty between existing formulations of the sea-spray source function that is parameterized in terms of wind speed and sea surface temperature is more than a factor of 2. Organic material substantially contributes to the composition of sea-spray aerosols, especially in biological active regions. Small sea-spray particles may be mainly composed of organic carbon with a decreasing contribution as particle size increases. The sizes in which organic carbon occurs are in the active CCN range and a change in composition may thus have a substantial effect on cloud droplet formation. A first attempt to include the OC fraction of sea-spray in a sea-spray source function was presented by O'Dowd et al. (2008). These authors proposed to use remotely sensed chlorophyll concentration data as a proxy for oceanic biological activity. An organics-chlorophyll relationship was determined by correlating chlorophyll satellite data and in-situ measurements of water insoluble organic compounds. This information was used together with the sea-spray source function to determine the surface flux of the combined inorganic/organic sea-spray particles (O'Dowd et al., 2008; Vignati et al., 2009; Albert et al., 2010). By introducing this methodology one inevitably introduces uncertainties due to the choice of a certain satellite instrument to obtain the chlorophyll data and the choice of the resolution and compositing period of the data. Other uncertainties that are introduced are due to the handling of the satellite data and the fit that is used in the organics-chlorophyll correlation. The organic fraction estimate can additionally be affected by the time period that is studied and the source function that is used to calculate the total sea-spray emission. We will first present a basis methodology to estimate the global emission of the submicron organic matter fraction of sea-spray. Starting from a first estimate of the annual global emission we have performed a sensitivity analysis regarding the above mentioned uncertainties. We found differences of up to at least 50% depending on the chosen parameterizations. Especially the choice of different source functions and the fit that was used in the organics-chlorophyll correlation were found to cause large deviations from our first estimate. From this we can conclude that the estimation of the fraction of organic matter in submicron sea-spray aerosol is still very uncertain. REFERENCES Albert, M.F.M.A., M. Schaap, G. de Leeuwand P.J.H. Builtjes (2010). Progress in the determination of the sea spray source function from satellite data. Journal of Integrative Environmental Sciences, accepted. O'Dowd, C.D. et al., 2008. A combined organic-inorganic sea-spray source function. Geophysical Research Letters, 35(L01801). Vignati E, Facchini MC, Rinaldi M, Scannell C, Ceburnis D, Sciare J, Kanakidou M, Myriokefalitakis S, Dentener F and O'Dowd CD. 2009. Global scale emission and distribution of sea spray aerosol: sea-salt and organic enrichment. Atmospheric Environment, accepted

Validation of IASI ozone profiles, using balloon sounding data

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