The future of spaceborne altimetry. Oceans and climate change: A long-term strategy

The ocean circulation and polar ice sheet volumes provide important memory and control functions in the global climate. Their long term variations are unknown and need to be understood before meaningful appraisals of climate change can be made. Satellite altimetry is the only method for providing global information on the ocean circulation and ice sheet volume. A robust altimeter measurement program is planned which will initiate global observations of the ocean circulation and polar ice sheets. In order to provide useful data about the climate, these measurements must be continued with unbroken coverage into the next century. Herein, past results of the role of the ocean in the climate system is summarized, near term goals are outlined, and requirements and options are presented for future altimeter missions. There are three basic scientific objectives for the program: ocean circulation; polar ice sheets; and mean sea level change. The greatest scientific benefit will be achieved with a series of dedicated high precision altimeter spacecraft, for which the choice of orbit parameters and system accuracy are unencumbered by requirements of companion instruments

Global mean sea surface computation based upon a combination of SEASAT and GEOS-3 satellite altimeter data

A mean sea surface map was computed for the global ocean areas between 70 deg N latitude and 62 deg S latitude based upon the 70 day SEASAT and 3.5 year GEOS-3 altimeter data sets. The mean sea surface is presented in the form of a global contour map and a 0.25 deg x 0.25 deg grid. A combination of regional adjustments based upon crossover techniques and the subsequent adjustment of the regional solutions into a global reference system was employed in order to minimize the effects of radial orbit error. A global map of the crossover residuals after the crossover adjustments are made is in good agreement with earlier mesoscale variability contour maps based upon the last month of SEASAT collinear data. This high level of agreement provides good evidence that relative orbit error was removed to the decimeter level on a regional basis. This represents a significant improvement over our previous maps which contained patterns, particularly in the central Pacific, which were due to radial orbit error. Long wavelength, basin scale errors are still present with a submeter amplitude due to errors in the PGS-S4 gravity model. Such errors can only be removed through the improvement of the Earth's gravity model and associated geodetic parameters

SPAN: Ocean science

The Space Physics Analysis Network (SPAN) is a multi-mission, correlative data comparison network which links space and Earth science research and data analysis computers. It provides a common working environment for sharing computer resources, sharing computer peripherals, solving proprietary problems, and providing the potential for significant time and cost savings for correlative data analysis. This is one of a series of discipline-specific SPAN documents which are intended to complement the SPAN primer and SPAN Management documents. Their purpose is to provide the discipline scientists with a comprehensive set of documents to assist in the use of SPAN for discipline specific scientific research

Reflecting on the first three years of Topex/Poseidon

satellite, in orbit since August 1992, is the first global ocean observing system specifically de-signed to study ocean dynamics. The satellite uses a state-of-the-art radar altimeter system to determine the sea level-the height of sea sur-face relative to a reference ellipsoid-with an unprecedented accuracy. It is supplying a wealth of new information on ocean circula-tion and the patterns of the global seasonal cy-cle, low-frequency wave dynamics, gyre-scale variabilities, ocean tides, and global mean sea level variations. These observations are being used to test ocean circulation theories and the ever-maturing computer models of ocean gen-eral circulation. T/P observations cover the global oceans from 66"s to 66"N every 10 days, allowing oceanographers to routinely monitor the dy-namic global ocean. For the first time, the ocean is being accurately sampled with suffi-cient spatial and temporal resolution to ad-dress its variability at frequencies and wavenumbers (spatial frequency) previously unattainable by in situ observations. The mis-sion was also designed to measure ocean tides, resulting in the most accurate deep ocean tide models to date. The tidal signals were then removed from the sea level measure-ments to make the data suitable for ocean cir-culation studies. The radar altimeter also measures wind speed and wave height, which are part of the mission's data product in addi-tion to sea level. Many results from the mission have been published in two special issues o

Costs of maternal health-related complications in Bangladesh.

This paper assesses both out-of-pocket payments for healthcare and losses of productivity over six months postpartum among women who gave birth in Matlab, Bangladesh. The hypothesis of the study objective is that obstetric morbidity leads women to seek care at which time out-of-pocket expenditure is incurred. Second, a woman may also take time out from employment or from doing her household chores. This loss of resources places a financial burden on the household that may lead to reduced consumption of usual but less important goods and use of other services depending on the extent to which a household copes up by using savings, taking loans, and selling assets. Women were divided into three groups based on their morbidity patterns: (a) women with a severe obstetric complication (n=92); (b) women with a less-severe obstetric complication (n=127); and (c) women with a normal delivery (n=483). Data were collected from households of these women at two time-points--at six weeks and six months after delivery. The results showed that maternal morbidity led to a considerable loss of resources up to six weeks postpartum, with the greatest financial burden of cost of healthcare among the poorest households. However, families coped up with loss of resources by taking loans and selling assets, and by the end of six months postpartum, the households had paid back more than 40% of the loans

Dynamic sea surface topography, gravity and improved orbit accuracies from the direct evaluation of SEASAT altimeter data

A method for the simultaneous solution of dynamic ocean topography, gravity and orbits using satellite altimeter data is described. A GEM-T1 based gravitational model called PGS-3337 that incorporates Seasat altimetry, surface gravimetry and satellite tracking data has been determined complete to degree and order 50. The altimeter data is utilized as a dynamic observation of the satellite's height above the sea surface with a degree 10 model of dynamic topography being recovered simultaneously with the orbit parameters, gravity and tidal terms in this model. PGS-3337 has a geoid uncertainty of 60 cm root-mean-square (RMS) globally, with the uncertainty over the altimeter tracked ocean being in the 25 cm range. Doppler determined orbits for Seasat, show large improvements, with the sub-30 cm radial accuracies being achieved. When altimeter data is used in orbit determination, radial orbital accuracies of 20 cm are achieved. The RMS of fit to the altimeter data directly gives 30 cm fits for Seasat when using PGS-3337 and its geoid and dynamic topography model. This performance level is two to three times better than that achieved with earlier Goddard earth models (GEM) using the dynamic topography from long-term oceanographic averages. The recovered dynamic topography reveals the global long wavelength circulation of the oceans with a resolution of 1500 km. The power in the dynamic topography recovery is now found to be closer to that of oceanographic studies than for previous satellite solutions. This is attributed primarily to the improved modeling of the geoid which has occurred. Study of the altimeter residuals reveals regions where tidal models are poor and sea state effects are major limitations

Progress and inequities in maternal mortality in Afghanistan (RAMOS-II): a retrospective observational study

Background The risk of maternal death in Afghanistan is among the highest in the world; however, the risks within the country are poorly understood. Subnational maternal mortality estimates are needed along with a broader understanding of determinants to guide future maternal health programmes. Here we aimed to study maternal mortality risk and causes, care-seeking patterns, and costs within the country. Methods We did a household survey (RAMOS-II) in the urban area of Kabul city and the rural area of Ragh, Badakshan. Questionnaires were administered to senior female household members and data were collected by a team of female interviewers with secondary school education. Information was collected about all deaths, livebirths, stillbirths, health-care access and costs, household income, and assets. Births were documented using a pregnancy history. We investigated all deaths in women of reproductive age (12–49 years) since January, 2008, using verbal autopsy. Community members; service providers; and district, provincial, and national officials in each district were interviewed to elicit perceptions of changes in maternal mortality risk and health service provision, along with programme and policy documentation of maternal care coverage. Findings Data were collected between March 2, 2011, and Oct 16, 2011, from 130 688 participants: 63 329 in Kabul and 67 359 in Ragh. The maternal mortality ratio in Ragh was quadruple that in Kabul (713 per 100 000 livebirths, 95% CI 553–873 in Ragh vs 166, 63–270 in Kabul). We recorded similar patterns for all other maternal death indicators, including the maternal mortality rate (1·7 per 1000 women of reproductive age, 95% CI 1·3–2·1 in Ragh vs 0·2, 0·1–0·3 in Kabul). Infant mortality also differed significantly between the two areas (115·5 per 1000 livebirths, 95% CI 108·6–122·3 in Ragh vs 24·8, 20·5–29·0 in Kabul). In Kabul, 5594 (82%) of 6789 women reported a skilled attendant during recent deliveries compared with 381 (3%) of 11 366 women in Ragh. An estimated 85% of women in Kabul and 47% in Ragh incurred delivery costs (mean US$66·20, IQR$61·30 in Kabul and $9·89,$11·87 in Ragh). Maternal complications were the third leading cause of death in women of reproductive age in Kabul, and the leading cause in Ragh, and were mainly due to hypertensive diseases of pregnancy. The maternal mortality rate decreased significantly between 2002 and 2011 in both Kabul (by 71%) and Ragh (by 84%), plus all other maternal mortality indicators in Ragh. Interpretation Remarkable maternal and other mortality reductions have occurred in Afghanistan, but the disparity between urban and rural sites is alarming, with all maternal mortality indicators significantly higher in Ragh than in Kabul. Customised service delivery is needed to ensure parity for different geographic and security settings

Delivering at Home or in a Health Facility? Health-Seeking Behaviour of Women and the Role of Traditional birth attendants in Tanzania.

Traditional birth attendants retain an important role in reproductive and maternal health in Tanzania. The Tanzanian Government promotes TBAs in order to provide maternal and neonatal health counselling and initiating timely referral, however, their role officially does not include delivery attendance. Yet, experience illustrates that most TBAs still often handle complicated deliveries. Therefore, the objectives of this research were to describe (1) women's health-seeking behaviour and experiences regarding their use of antenatal (ANC) and postnatal care (PNC); (2) their rationale behind the choice of place and delivery; and to learn (3) about the use of traditional practices and resources applied by traditional birth attendants (TBAs) and how they can be linked to the bio-medical health system. Qualitative and quantitative interviews were conducted with over 270 individuals in Masasi District, Mtwara Region and Ilala Municipality, Dar es Salaam, Tanzania. The results from the urban site show that significant achievements have been made in terms of promoting pregnancy- and delivery-related services through skilled health workers. Pregnant women have a high level of awareness and clearly prefer to deliver at a health facility. The scenario is different in the rural site (Masasi District), where an adequately trained health workforce and well-equipped health facilities are not yet a reality, resulting in home deliveries with the assistance of either a TBA or a relative. Instead of focusing on the traditional sector, it is argued that more attention should be paid towards (1) improving access to as well as strengthening the health system to guarantee delivery by skilled health personnel; and (2) bridging the gaps between communities and the formal health sector through community-based counselling and health education, which is provided by well-trained and supervised village health workers who inform villagers about promotive and preventive health services, including maternal and neonatal health

Analyzing the discharge regime of a large tropical river through remote sensing, ground-based climatic data, and modeling

This study demonstrates the potential for applying passive microwave satellite sensor data to infer the discharge dynamics of large river systems using the main stem Amazon as a test case. The methodology combines (1) interpolated ground-based meteorological station data, (2) horizontally and vertically polarized temperature differences (HVPTD) from the 37-GHz scanning multichannel microwave radiometer (SMMR) aboard the Nimbus 7 satellite, and (3) a calibrated water balance/water transport model (WBM/WTM). Monthly HVPTD values at 0.25° (latitude by longitude) resolution were resampled spatially and temporally to produce an enhanced HVPTD time series at 0.5° resolution for the period May 1979 through February 1985. Enhanced HVPTD values were regressed against monthly discharge derived from the WBM/WTM for each of 40 grid cells along the main stem over a calibration period from May 1979 to February 1983 to provide a spatially contiguous estimate of time-varying discharge. HVPTD-estimated flows generated for a validation period from March 1983 to February 1985 were found to be in good agreement with both observed arid modeled discharges over a 1400-km section of the main stem Amazon. This span of river is bounded downstream by a region of tidal influence and upstream by low sensor response associated with dense forest canopy. Both the WBM/WTM and HVPTD-derived flow rates reflect the significant impact of the 1982–1983 El Niño-;Southern Oscillation (ENSO) event on water balances within the drainage basin