249 research outputs found
Seasonal variation of the mesospheric inversion layer, thunderstorms and mesospheric ozone over India
Temperature and ozone volume mixing ratio profiles obtained from the Halogen
Occultation Experiment (HALOE) aboard the Upper Atmospheric Research
Satellite
(UARS) over India and over the open ocean to the south during the period
1991-2001 are analyzed to study the characteristic features of the Mesospheric
Inversion Layer (MIL) at 70 to 85 km altitude and its relation with the ozone
mixing ratio at this altitude. We have also analyzed both the number of
lightning flashes measured by the Optical Transient Detector (OTD) onboard the
MicroLab-1 satellite for the period April 1995 - March 2000 and ground-based
thunderstorm data collected from 78 widespread Indian observatories for the
same period to show that the MIL amplitude and thunderstorm activity are
correlated. All the data sets examined exhibit a semiannual variation. The
seasonal variation of MIL amplitude and the frequency of occurrence of the
temperature inversion indicate a fairly good correlation with the seasonal
variation of thunderstorms and the average ozone volume mixing ratio across the
inversion layer. The observed correlation between local thunderstorm activity,
MIL amplitude and mesospheric ozone volume mixing ratio are explained by the
generation, upward propagation and mesospheric absorption of gravity waves
produced by thunderstorms.Comment: 45 pages, 10 figures, 2 tables, PDF format, version published in
Journal of Geophysical Research-Atmospher
Unlocking Pre-1850 Instrumental Meteorological Records: A Global Inventory
Instrumental meteorological measurements from periods prior to the start of national weather services are designated “early instrumental data.” They have played an important role in climate research as they allow daily to decadal variability and changes of temperature, pressure, and precipitation, including extremes, to be addressed. Early instrumental data can also help place twenty-first century climatic changes into a historical context such as defining preindustrial climate and its variability. Until recently, the focus was on long, high-quality series, while the large number of shorter series (which together also cover long periods) received little to no attention. The shift in climate and climate impact research from mean climate characteristics toward weather variability and extremes, as well as the success of historical reanalyses that make use of short series, generates a need for locating and exploring further early instrumental measurements. However, information on early instrumental series has never been electronically compiled on a global scale. Here we attempt a worldwide compilation of metadata on early instrumental meteorological records prior to 1850 (1890 for Africa and the Arctic). Our global inventory comprises information on several thousand records, about half of which have not yet been digitized (not even as monthly means), and only approximately 20% of which have made it to global repositories. The inventory will help to prioritize data rescue efforts and can be used to analyze the potential feasibility of historical weather data products. The inventory will be maintained as a living document and is a first, critical, step toward the systematic rescue and reevaluation of these highly valuable early records. Additions to the inventory are welcome
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