292 research outputs found
Blended probabilistic nowcasting with the IMPROVER post-processing system
Presentación realizada en la 3rd European Nowcasting Conference, celebrada en la sede central de AEMET en Madrid del 24 al 26 de abril de 2019
CLARREO Cornerstone of the Earth Observing System: Measuring Decadal Change Through Accurate Emitted Infrared and Reflected Solar Spectra and Radio Occultation
The Climate Absolute Radiance and Refractivity Observatory (CLARREO) is one of four Tier 1 missions recommended by the recent NRC Decadal Survey report on Earth Science and Applications from Space (NRC, 2007). The CLARREO mission addresses the need to provide accurate, broadly acknowledged climate records that are used to enable validated long-term climate projections that become the foundation for informed decisions on mitigation and adaptation policies that address the effects of climate change on society. The CLARREO mission accomplishes this critical objective through rigorous SI traceable decadal change observations that are sensitive to many of the key uncertainties in climate radiative forcings, responses, and feedbacks that in turn drive uncertainty in current climate model projections. These same uncertainties also lead to uncertainty in attribution of climate change to anthropogenic forcing. For the first time CLARREO will make highly accurate, global, SI-traceable decadal change observations sensitive to the most critical, but least understood, climate forcings, responses, and feedbacks. The CLARREO breakthrough is to achieve the required levels of accuracy and traceability to SI standards for a set of observations sensitive to a wide range of key decadal change variables. The required accuracy levels are determined so that climate trend signals can be detected against a background of naturally occurring variability. Climate system natural variability therefore determines what level of accuracy is overkill, and what level is critical to obtain. In this sense, the CLARREO mission requirements are considered optimal from a science value perspective. The accuracy for decadal change traceability to SI standards includes uncertainties associated with instrument calibration, satellite orbit sampling, and analysis methods. Unlike most space missions, the CLARREO requirements are driven not by the instantaneous accuracy of the measurements, but by accuracy in the large time/space scale averages that are key to understanding decadal changes
Doublet Pulse Coherent Laser Radar for Tracking of Resident Space Objects
In this paper, the development of a long range ladar system known as ExoSPEAR at NASA Langley Research Center for tracking rapidly moving resident space objects is discussed. Based on 100 W, nanosecond class, near-IR laser, this ladar system with coherent detection technique is currently being investigated for short dwell time measurements of resident space objects (RSOs) in LEO and beyond for space surveillance applications. This unique ladar architecture is configured using a continuously agile doublet-pulse waveform scheme coupled to a closed-loop tracking and control loop approach to simultaneously achieve mm class range precision and mm/s velocity precision and hence obtain unprecedented track accuracies. Salient features of the design architecture followed by performance modeling and engagement simulations illustrating the dependence of range and velocity precision in LEO orbits on ladar parameters are presented. Estimated limits on detectable optical cross sections of RSOs in LEO orbits are discussed
Recommended from our members
Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Juveniles, 2003-2004 Annual Report.
This report provides information on PIT-tagging of wild Chinook salmon parr in Idaho in 2003 and the subsequent monitoring of these fish and similarly tagged fish from Oregon. We report estimated parr-to-smolt survival and arrival timing of these fish at Lower Granite Dam, as well as interrogation data collected at several other sites throughout the Snake and Columbia River system. This research continues studies that began under Bonneville Power Administration (BPA) funding in 1991. Results from previous study years were reported by Achord et al. (1994; 1995a,b; 1996a; 1997; 1998; 2000; 2001a,b; 2002, 2003, 2004). Goals of this ongoing study are: (1) Characterize the migration timing and estimate parr-to-smolt survival of different stocks of wild Snake River spring/summer Chinook salmon smolts at Lower Granite Dam. (2) Determine whether consistent migration patterns are apparent. (3) Determine what environmental factors influence migration patterns. (4) Characterize the migration behavior and estimate survival of different wild juvenile fish stocks as they emigrate from their natal rearing areas. This study provides critical information for recovery planning, and ultimately recovery for these ESA-listed wild fish stocks. In 2003-2004, we also continued to measure water temperature, dissolved oxygen, specific conductance, turbidity, water depth, and pH at five monitoring stations in the Salmon River Basin, Idaho for the Baseline Environmental Monitoring Program. These data, along with parr/smolt migration, survival, and timing data, will help to discern patterns or characteristic relationships between fish movement/survival and environmental factors
Design and Build a Compact Raman Sensor for Identification of Chemical Composition
A compact remote Raman sensor system was developed at NASA Langley Research Center. This sensor is an improvement over the previously reported system, which consisted of a 532 nm pulsed laser, a 4-inch telescope, a spectrograph, and an intensified charge-coupled devices (CCD) camera. One of the attractive features of the previous system was its portability, thereby making it suitable for applications such as planetary surface explorations, homeland security and defense applications where a compact portable instrument is important. The new system was made more compact by replacing bulky components with smaller and lighter components. The new compact system uses a smaller spectrograph measuring 9 x 4 x 4 in. and a smaller intensified CCD camera measuring 5 in. long and 2 in. in diameter. The previous system was used to obtain the Raman spectra of several materials that are important to defense and security applications. Furthermore, the new compact Raman sensor system is used to obtain the Raman spectra of a diverse set of materials to demonstrate the sensor system's potential use in the identification of unknown materials
Recommended from our members
Bone morphogenetic protein 4 (BMP4) loss-of-function variant associated with autosomal dominant Stickler syndrome and renal dysplasia.
Stickler syndrome is a genetic disorder that can lead to joint problems, hearing difficulties and retinal detachment. Genes encoding collagen types II, IX and XI are usually responsible, but some families have no causal variant identified. We investigate a variant in the gene encoding growth factor BMP4 in a family with Stickler syndrome with associated renal dysplasia. Next generation sequencing of the coding region of COL2A1, COL11A1 and a panel of genes associated with congenital anomalies of the kidney and urinary tract (CAKUT) was performed. A novel heterozygous BMP4 variant causing a premature stop codon, c. 130G>T, p.(Gly44Ter), which segregated with clinical features of Stickler syndrome in multiple family members, was identified. No variant affecting gene function was detected in COL2A1 or COL11A1. Skin fibroblasts were cultured with and without emetine, and the mRNA extracted and analysed by Sanger sequencing to assess whether the change was causing nonsense-mediated decay. Nonsense-mediated decay was not observed from the extracted BMP4 mRNA. BMP4 is a growth factor known to contribute to eye development in animals, and gene variants in humans have been linked to microphthalmia/anophthalmia as well as CAKUT. The variant identified here further demonstrates the importance of BMP4 in eye development. This is the first report of a BMP4 DNA variant causing Stickler syndrome, and we suggest BMP4 be added to standard diagnostic gene panels for this condition
The Future of Single- to Multi-band Detector Technologies: Review
Using classical optical components such as filters, prisms and gratings to separate the desired wavelengths before they reach the detectors results in complex optical systems composed of heavy components. A simpler system will result by utilizing a single optical system and a detector that responds separately to each wavelength band. Therefore, a continuous endeavors to develop the capability to reliably fabricate detector arrays that respond to multiple wavelength regions. In this article, we will review the state-of-the-art single and multicolor detector technologies over a wide spectral-range, for use in space-based and airborne remote sensing applications. Discussions will be focused on current and the most recently developed focal plane arrays (FPA) in addition to emphasizing future development in UV-to-Far infrared multicolor FPA detectors for next generation space-based instruments to measure water vapor and greenhouse gases. This novel detector component will make instruments designed for these critical measurements more efficient while reducing complexity and associated electronics and weight. Finally, we will discuss the ongoing multicolor detector technology efforts at NASA Langley Research Center, Jet Propulsion Laboratory, Rensselaer Polytechnic Institute, and others
Living with Uncertainty
The last few years have seen a major rethinking of some of the hallowed assumptions of range ecology and range management practice. This book examines the management of policy implications of this new ecological thinking for pastoral development in dryland areas. With examples drawn from all over Africa, the contributors examine the consequences of living with uncertainty for pastoral development planning, range and fodder management, drought responses, livestock marketing, resource tenure, institutional development and pastoral administration
The status of health services in the 15 counties of Liberia
Aim: Liberia, situated at the West African coast, is composed of 15 counties with an economic gradient steeply decreasing from the Northwest to the Southeast. Health-related activities by government action in the 15 counties concentrate on the areas of family planning, antenatal and delivery care, as well as immunization, health workforce and infrastructure. The differences in this regard between the 15 Liberian counties will be reviewed.
Methods: A narrative review is employed, making use of the recent international and national documents, relevant literature and available information from the following primary and secondary sources and databases.
Results: The results point to gross differences between the 15 counties of Liberia in terms of health service provision. The overall readiness based on defined indicators for all 701 facilities was 59% with a range between facilities at the level of counties of 50% to 65%; for family planning services 88% (range 65% – 100%); for antenatal care 62% (range 55% – 100%); for immunization coverage 76% (range 66% – 86%). The health workforce of Liberia comprises 11.8 health workers per 10.000 population, WHO target is 23, the counties range from 8.0 to 15.7. Similarly, according to WHO standards, there should be 2 health facilities per 10.000 inhabitants, Liberia comes up to 1.9 however the counties range from 1.1 – 3.0 per 10.000.
Conclusions: It is obvious that across almost all areas of women and child health and health services in general there exist large differences between counties, which points to considerable health inequities in this country. The government of Liberia should consider reallocating the available resources per number of population instead of accepting historical developments, however with a correction factor in favou of disadvantaged regions and population groups
- …