A novel satellite-based ocean monitoring system for Mexico

To analyze patterns in marine productivity, harmful algal blooms, thermal stress in coral reefs, and oceanographic processes, optical and biophysical marine parameters, such as sea surface temperature, and ocean color products, such as chlorophyll-a concentration, diffuse attenuation coefficient, total suspended matter concentration, chlorophyll fluorescence line height, and remote sensing reflectance, are required. In this paper we present a novel automatic Satellite-based Ocean Monitoring System (SATMO) developed to provide, in near real-time, continuous spatial data sets of the above-mentioned variables for marine-coastal ecosystems in the Gulf of Mexico, northeastern Pacific Ocean, and western Caribbean Sea, with 1 km spatial resolution. The products are obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) images received at the Direct Readout Ground Station (located at CONABIO) after each overpass of the Aqua and Terra satellites. In addition, at the end of each week and month the system provides composite images for several ocean products, as well as weekly and monthly anomaly composites for chlorophyll-a concentration and sea surface temperature. These anomaly data are reported for the first time for the study region and represent valuable information for analyzing time series of ocean color data for the study of coastal and marine ecosystems in Mexico, Central America, and the western Caribbean

Monitoring holopelagic Sargassum spp. along the Mexican Caribbean coast: understanding and addressing user requirements for satellite remote sensing

Massive influxes of holopelagic Sargassum spp. (Sargassum natans and S. fluitans) have been causing major economic, environmental and ecological problems along the Caribbean coast of Mexico. Predicting the arrival of the sargassum as an aid to addressing these problems is a priority for the government, coastal communities and the society; both mitigating the impacts and providing opportunities for its use. Lack of data concerning precise locations and times of sargassum beachings means that public and private funds are being spent inefficiently and most actions are reactive. The dynamic nature of sargassum beachings/influxes render conventional ground-based monitoring insufficient. Earth observation and cloud-based processing services offer tools to track, quantify and understand sargassum beaching remotely in a frequent, systematic and reliable manner with the temporal and spatial resolutions required for its management. In order to find the right solutions to address this problem, in this paper the needs and requirements of stakeholders are taken into consideration for the development of an Earth observation-based service to monitor sargassum along the Mexican Caribbean coast. Routine monitoring of sargassum over a large area will be cost effective and help mitigate the negative effects of sargassum influxes. The combination of imagery from Planet, specifically their SuperDove systems that provide daily data at 3 m spatial resolutions, with the freely available EU Copernicus data would be useful for many different stakeholders and potential users. A prototype of the service is presented, based on the main user requirements. The system would enable public and private organizations to allocate resources appropriately in affected areas quickly and efficiently, thereby minimizing economic, social and environmental impacts and enhancing the resilience of local communities. It would also assist the sargassum industry in the collection of fresh algae for onward processing. The system could easily be implemented for similar types of environmental monitoring in the Greater Caribbean and beyond

Host and environment factors for exposure to poisons: a case-control study of preschool children in Thailand

Objective—To identify host and environment characteristics associated with poison exposure among preschool children in Thailand. Setting—A matched case-control study in 20 public hospitals in Khon Kaen province. Methods—Cases comprised 100 consecutive preschool children attending hospital between September 1997 and February 1999 because of reported exposure to a poison. Controls were three children matched by age, sex and area of residence to each case, who had never attended a hospital for this reason. Risk factors were elicited by interviewing the children's caregivers at their homes using a structured questionnaire and analyzed using conditional logistic regression. Results—Number of siblings, whether the child was "medicine eating" and "rushing to explore new objects", the child's activities while the caregiver was working during the daytime, the child's distance from the caregiver while the caregiver was working, whether the child was taken to a non-agricultural worksite, and the number of used containers around the residence, were all statistically significant in univariate analyses. However, when all significant variables were included in a multivariate model, only "medicine eating" and the number of used containers around the residence remained statistically significant. Conclusion—Attention to "medicine eating" and used containers through increased supervision could be a protective factor against poison exposure for these children. To reduce risk, caregivers should not refer to medicines as foods and used containers should be systematically collected for disposal or recycling

Initial synchronization procedure for UMTS-FDD mode in FPGA

An implementation in FPGA of an algorithm suited for initial synchronization in mobile terminals for UMTS-FDD has been considered. Since software realization requires large amounts of MIPS and memory, the proposal allows a physical realization of a hardware system saving area and power which are critical in mobile terminal

Mapping of the spatial distribution of benthic habitats in the Gulf of Batabanó using Landsat-7 images

The spatial distribution of benthic habitats in the Gulf of Batabanó obtained by remote sensing, using five images from the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) satellite sensor, is reported for the first time. The map covers a total underwater area of 21,305 km2 and is presented at the 1:250,000 scale. Five benthic habitats were identified within this area and located using the supervised classification technique: medium- to high-density seagrass, low-density seagrass, sand with scarce vegetation, mud with scarce vegetation, and rock. Seagrass covers 64.85% (13,818 km2) of the total area, while 35.15% (7,487 km2) corresponds to the remaining benthic habitats with or without scarce vegetation. Both the underwater vegetation (seagrass and macro seaweed) and the substratum types were considered. Results were confirmed by in situ measurements obtained from three research cruises between 2003 and 2005. This map represents an important characterization of the Cuban platform waters in order to better understand these ecosystems, and can be used in future change detection analyses to monitor the health of benthic habitats in the Gulf of Batabanó.

Seasonal pattern of the chlorophyll-a in a coastal lagoon from the Southern Baja California (Mexico), described with in situ observations and MODIS-Aqua imagery

This study aims to estimate, with a climatology perspective, the average seasonal pattern of phytoplankton biomass (SP-PBavg) and its distribution in Bahia Magdalena (Mexico) as a baseline to evaluate PB changes in future studies. This lagoon is in a semi-arid region, lacks river discharges, and channels with vegetation are limited at the north and south zones. SP-PBavg was estimated with chlorophyll-a (chl-a) data obtained in 21 sites on daily MODISAqua imagery (2002—2013; n = 2,418) from a ready-to-use public database. The first step was to establish criteria to use imagery and validate with in situ observations taken in 14 sites (2002—2011; n = 312). MODIS-Aqua overestimated chl-a (mean ± confidence interval95: 5.09 ± 0.97 mg m−3; n = 225); with differences among sites. There were no differences near the inlet lagoon (p <0.05), where the water characteristics are Case-1 while values were significantly higher in the eastern shore and two or three times higher in the mouth of north and south channels, whose water characteristics are similar to Case-2. Multivariate statistical methods allow defining zones into the lagoon and describe their SP-PBavg with both in situ and MODIS Aqua data, but the former’s sample size was small, and the patterns were only delineated. In the inlet surroundings, chl-a peaks from March/April to June/July. On the eastern shore, where MODIS Aqua and in situ data were correlated, despite concentration differences, chla is higher from March/April to October, with peaks in June and September. In the mouth of internal channels, chl-a was higher than other sites and during a longer period; however, the very high MODIS-Aqua values suggest that the satellite also detects organic matter supplied by phytoplankton and other vegetables, which explain the high lagoon’s productivity. These results validate the use of MODIS Aqua imagery to describe the chl-a seasonal patterns in the sea’s vicinit

Natural Variability of Surface Oceanographic Conditions in the Offshore Gulf of Mexico

This work characterizes patterns of temporal variability in surface waters of the central Gulf of Mexico. We examine remote-sensing based observations of sea surface temperature (SST), wind speed, sea surface height anomaly (SSHA), chlorophyll- a concentration (Chl- a) and Net Primary Production (NPP), along with model predictions of mixed layer depth (MLD), to determine seasonal changes and long-term trends in the central Gulf of Mexico between the early 1980s and 2012. Specifically, we examine variability in four quadrants of the Gulf of Mexico (water depth \u3e1000. m). All variables show strong seasonality. Chl- a and NPP show positive anomalies in response to short-term increases in wind speed and to cold temperature events. The depth of the mixed layer (MLD) directly and significantly affects primary productivity throughout the region. This relationship is sufficiently robust to enable real-time estimates of MLD based on satellite-based estimates of NPP. Over the past 15-20. years, SST, wind speed, and SSHA show a statistically significant, gradual increase. However, Chl. -a and NPP show no significant trends over this period. There has also been no trend in the MLD in the Gulf of Mexico interior. The positive long-term trend in wind speed and SST anomalies is consistent with the warming phase of the Atlantic Multidecadal Oscillation (AMO) that started in the mid-90s. This also coincides with a negative trend in the El Niño/Southern Oscillation Multivariate ENSO Index (MEI) related to an increase in the frequency of cooler ENSO events since 1999-2000. The results suggest that over decadal scales, increasing temperature, wind speed, and mesoscale ocean activity have offsetting effects on the MLD. The lack of a trend in MLD anomalies over the past 20. years explains the lack of long-term changes in chlorophyll concentration and productivity over this period in the Gulf. Understanding the background of seasonal and long-term variability in these ocean characteristics is important to interpret changes in ocean health due to episodic natural and anthropogenic events and long term climate changes or development activities. With this analysis we provide a baseline against which such changes can be measured