English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Ground-based measurements of atmospheric parameters have been carriedout for more than 20 years at the Network for the Detection of AtmosphericComposition Change (NDACC) station at Thule Air Base(76.5°N, 68.8°W), on the north-western coast of Greenland. Various instrumentsdedicated to the study of the lower and middle polar atmosphereare installed at Thule in the framework of a long standingcollaboration among Danish, Italian, and US research institutes and universities.This effort aims at monitoring the composition, structure anddynamics of the polar stratosphere, and at studying the Arctic energybudget and the role played by different factors, such as aerosols, watervapour, and surface albedo. During the International Polar Year (IPY),in winter 2008-2009, an intensive measurement campaign was conductedat Thule within the framework of the IPY project “Ozone layer and UVradiation in a changing climate evaluated during IPY” (ORACLE-O3)which sought to improve our understanding of the complex mechanismsthat lead to the Arctic stratospheric O3 depletion. The campaign involveda lidar system, measuring aerosol backscatter and depolarization ratiosup to 35 km and atmospheric temperature profiles from 25 to 70 km altitude,a ground-based millimeter-wave spectrometer (GBMS) used to derivestratospheric mixing ratio profiles of different chemical speciesinvolved in the stratospheric ozone depletion cycle, and then ground-basedradiometers and a Cimel sunphotometer to study the Arctic radiativebudget at the surface. The observations show that the surface radiationbudget is mainly regulated by the longwave component throughout mostof the year. Clouds have a significant impact contributing to enhance therole of longwave radiation. Besides clouds, water vapour seasonal changes produce the largest modification in the shortwave component at the surface,followed by changes in surface albedo and in aerosol amounts. Forwhat concerns the middle atmosphere, during the first part of winter2008-2009 the cold polar vortex allowed for the formation of polar stratosphericclouds (PSCs) which were observed above Thule by means of thelidar. This period was also characterized by GBMS measurements of lowvalues of O3 due to the catalytic reactions prompted by the PSCs. In mid-January, as the most intense Sudden Stratospheric Warming event everobserved in the Arctic occurred, GBMS and lidar measurements of O3,N2O, CO and temperature described its evolution as it propagated fromthe upper atmosphere to the lower stratosphere

Observations of surface radiation and stratospheric processes at Thule Air Base, Greenland, during the IPY