Assessment of two aerosol optical thickness retrieval algorithms applied to MODIS aqua and terra measurements in Europe

© Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 LicenseThe aim of the present study is to validate AOT (aerosol optical thickness) and A° ngström exponent (α), obtained from MODIS (MODerate resolution Imaging Spectroradiometer) Aqua and Terra calibrated level 1 data (1 km horizontal resolution at ground) with the SAER (Satellite AErosol Retrieval) algorithm and with MODIS Collection 5 (c005) standard product retrievals (10 km horizontal resolution), against AERONET (AErosol RObotic NETwork) sun photometer observations over land surfaces in Europe. An inter-comparison of AOT at 0.469 nm obtained with the two algorithms has also been performed. The time periods investigated were chosen to enable a validation of the findings of the two algorithms for a maximal possible variation in sun elevation. The satellite retrievals were also performed with a significant variation in the satellite-viewing geometry, since Aqua and Terra passed the investigation area twice a day for several of the cases analyzed. The validation with AERONET shows that the AOT at 0.469 and 0.555 nm obtained with MODIS c005 is within the expected uncertainty of one standard deviation of the MODIS c005 retrievals (1AOT =±0.05±0.15 ·AOT). The AOT at 0.443 nm retrieved with SAER, but with a much finer spatial resolution, also agreed reasonably well with AERONET measurements. The majority of the SAER AOT values are within the MODIS c005 expected uncertainty range, although somewhat larger average absolute deviation occurs compared to the results obtained with the MODIS c005 algorithm. The discrepancy between AOT from SAER and AERONET is, however, substantially larger for the wavelength 488 nm. This means that the values are, to a larger extent, outside of the expected MODIS uncertainty range. In addition, both satellite retrieval algorithms are unable to estimate accurately, although the MODIS c005 algorithm performs better. Based on the inter-comparison of the SAER and MODIS c005 algorithms, it was found that SAER on the whole is able to obtain results within the expected uncertainty range of MODIS Aqua and Terra observations.Peer reviewe

Heated tobacco products: another tobacco industry global strategy to slow progress in tobacco control.

There has been a global decline in tobacco consumption that, if continued, will negatively impact the tobacco industry's profits. This decline led the industry to invent and market new products, including heated tobacco products (HTP). HTP are an extension of the industry's strategies to undermine government's tobacco regulatory efforts as they are being promoted as part of the solution for the tobacco epidemic. Under the moniker of 'harm reduction', the tobacco companies are attempting to rehabilitate their reputation so they can more effectively influence governments to roll back existing tobacco control policies or create exemptions for their HTP. Rolling back tobacco control policies will make it easier for the companies to renormalise tobacco use to increase social acceptability for all their products. When regulations are absent or when loopholes exist in classifying HTP as a tobacco product (thus subject to all tobacco control regulations), the industry's marketing of HTP is making these products more visible to the public and more accessible. Governments need to ensure that HTP are regulated as tobacco products or drugs and reject partnerships with the tobacco companies to promote 'harm reduction'. The tobacco companies remain the vector of the tobacco-caused epidemic and cannot be part of the global tobacco control solution

Use of an Evidence‐Based Guideline for Management of Side Effects from Long‐Acting Reversible Contraceptives: A Quality Improvement Report

Introduction Many health care providers believe that women who initiate long‐acting reversible contraceptives (LARC) discontinue the method because of side effects too soon for the method to be economical. The purpose of this quality improvement project was to implement and evaluate an evidence‐based telephone triage nursing guideline for management of side effects of LARC with an ultimate goal of reducing the number of early discontinuations. Process A telephone triage guideline was adapted from the Contraceptive Choice Project\u27s Clinician Call Back System, supplemented with evidence‐based resources, and approved by clinicians at 2 community women\u27s health and midwifery offices. Baseline retrospective data were collected on all women over the age of 18 who had LARC inserted at the 2 sites in the year prior to guideline implementation and in the 3 months after implementation. Rates of LARC removal at or before 3 months postinsertion, before and after guideline implementation, were evaluated. Outcomes Approximately 1 in 5 women called for help managing LARC side effects. Of the callers, 3 of 32 (9.4%) women receiving standard care discontinued their LARC prior to 3 months, whereas 0 of 24 women who were triaged using the guideline discontinued their LARC prior to 3 months (P = .12). Cramping, bleeding, and malposition or expulsion were the most common concerns and reasons for discontinuation. Discussion Fewer women than anticipated called to report side effects, and even fewer chose to discontinue their LARC early. There were fewer discontinuations with guideline use, but this was not a statistically significant difference. Most women did not discontinue their LARC early for any reason, including side effects

Vigencia de Nellie Campobello

Non

Trends in MODIS and AERONET derived aerosol optical thickness over Northern Europe

Long-term Aqua and Terra MODIS (MODerate resolution Imaging Spectroradiometer) Collections 5.1 and 6.1 (c051 and c061, respectively) aerosol data have been combined with AERONET (AERosol RObotic NETwork) ground-based sun photometer observations to examine trends in aerosol optical thickness (AOT, at 550 nm) over Northern Europe for the months April to September. For the 1927 and 1559 daily coincident measurements that were obtained for c051 and c061, respectively, MODIS AOT varied by 86 and 90%, respectively, within the predicted uncertainty of one standard deviation of the retrieval over land (ΔAOT = ±0.05 ± 0.15·AOT). For the coastal AERONET site Gustav Dalen Tower (GDT), Sweden, larger deviations were found for MODIS c051 and c061 (79% and 75%, respectively, within predicted uncertainty). The Baltic Sea provides substantially better statistical representation of AOT than the surrounding land areas and therefore favours the investigations of trends in AOT over the region. Negative trends of 1.5% and 1.2% per year in AOT, based on daily averaging, were found for the southwestern Baltic Sea from MODIS c051 and c061, respectively. This is in line with a decrease of 1.2% per year in AOT at the AERONET station Hamburg. For the western Gotland Basin area, Sweden, negative trends of 1.5%, 1.1% and 1.6% per year in AOT have been found for MODIS c051, MODIS c061 and AERONET GDT, respectively. The strongest trend of –1.8% per year in AOT was found for AERONET Belsk, Poland, which can be compared to –1.5% per day obtained from MODIS c051 over central Poland. The trends in MODIS and AERONET AOT are nearly all statistically significant at the 95% confidence level. The strongest aerosol sources are suggested to be located southwest, south and southeast of the investigation area, although the highest prevalence of pollution events is associated with air mass transport from southwest.Peer reviewe