Tropospheric and lower stratospheric aerosol backscatter data obtained from a calibrated backscatter lidar at Pasadena, California (34 deg N latitude) over the 1984-1993 period clearly indicate ...tightly coupled aerosol optical properties in the upper troposphere and lower stratosphere in the winter and early spring, due to the active midlatitude stratospheric-tropospheric (ST) exchange processes occurring at this time of year. Lidar data indicate that during pre-Pinaturbo background conditions, the subsequent purging of the aerosol in the upper troposphere caused a significant reduction in the aerosol content throughout the 8 - 18 km altitude region in the early spring period. The post-Pinatubo evidence of intense exchange in the winter and early spring is a significant increase in the upper tropospheric aerosol content, such that the backscatter levels reach values nearly equivalent to the enhanced backscatter levels existing in the lower stratosphere. The calculated stratospheric mass extrusion rate is consistent with a 45-day lifetime of lower stratospheric aerosol during this part of the year, which implies that midlatitude ST exchange is a significant sink for stratospheric aerosol.
The atmospheric lidar remote sensing groups of NOAA Environmental Technology Laboratory, NASA Marshall Space Flight Center, and Jet Propulsion Laboratory have developed and flown a scanning, 1 Joule ...per pulse, CO2 coherent Doppler lidar capable of mapping a three-dimensional volume of atmospheric winds and aerosol backscatter in the planetary boundary layer, free troposphere, and lower stratosphere. Applications include the study of severe and non-severe atmospheric flows, intercomparisons with other sensors, and the simulation of prospective satellite Doppler lidar wind profilers. Examples of wind measurements are given for the marine boundary layer and near the coastline of the western United States.
The NASA Earth Science Technology Office (ESTO) recently updated its investment strategy in the area of lidar technologies as it pertains to NASA's Earth Science measurement goals in the next decade. ...The last ESTO lidar strategy was documented in 2006. The current (2016) report assesses the state-of-the-art in lidar technologies a decade later. Lidar technology maturation in the past decade has been evaluated, and the ESTO investment strategy is updated and laid out in this report according to current NASA Earth science measurement needs and new emerging technologies.
BACKGROUND AND AIMS: Recent phylogenetic analysis has placed the aquatic family Hydatellaceae as an early-divergent angiosperm. Understanding seed dormancy, germination and desiccation tolerance of ...Hydatellaceae will facilitate ex situ conservation and advance hypotheses regarding angiosperm evolution. METHODS: Seed germination experiments were completed on three species of south-west Australian Hydatellaceae, Trithuria austinensis, T. bibracteata and T. submersa, to test the effects of temperature, light, germination stimulant and storage. Seeds were sectioned to examine embryo growth during germination in T. austinensis and T. submersa. KEY RESULTS: Some embryo growth and cell division in T. austinensis and T. submersa occurred prior to the emergence of an undifferentiated embryo from the seed coat ('germination'). Embryo differentiation occurred later, following further growth and a 3- to 4-fold increase in the number of cells. The time taken to achieve 50 % of maximum germination for seeds on water agar was 50, 35 and 37 d for T. austinensis, T bibracteata and T. submersa, respectively. CONCLUSIONS: Seeds of Hydatellaceae have a new kind of specialized morphophysiological dormancy in which neither root nor shoot differentiates until after the embryo emerges from the seed coat. Seed biology is discussed in relation to early angiosperm evolution, together with ex situ conservation of this phylogenetically significant group.
The advantages of airborne hyperspectral longwave-infrared imaging for emissions monitoring are described in the context of urban-industrial environments. These benefits are illustrated by means of ...several case studies.
Several ammonia emitting fumarole fields have recently been exposed along the southeastern shoreline of the Salton Sea in Imperial County, California. A complex assemblage of sulfate minerals, many ...containing ammonium ion, are associated with the fumaroles. The distribution of these sulfates was mapped by remote sensing with the Mako LWIR hyperspectral sensor. The most common minerals tended to form somewhat concentric discontinuous rings. Outwardly from the central fumarole vent, they were: mascagnite/boussingaultite, gypsum, nitratine and bloedite, respectively. Ground truth surveys coupled with laboratory analyses were generally in good agreement with the remote sensing results.
A multi-year study of ammonia emissions from a recently exposed geothermal fumarole field at the SE edge of the Salton Sea (Southern California) is described. The work makes extensive use of airborne ...thermal-infrared hyperspectral imagery acquired over the field site.
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