Climate processes

Abstract:

From 2017 to 2019, vast swathes of eastern Australia were affected by the severe and devastating Tinderbox Drought. Here, we present the first extended drought climatology for New England, spanning 1880 to 2022, and explore trends in drought characteristics over the past 142 years. We use newly recovered historical temperature and rainfall observations, the latest version of the Australian Bureau of Meteorology’s gridded rainfall dataset and a global gridded extreme dataset to assess changes in precipitation signatures and temperature events during droughts. Our analysis identifies 32 meteorological droughts from 1880 to 2022, lasting from 7 months to over 7 years. The climatology also reveals a change in the nature of drought, with a shift from events characterised by warm season rainfall deficiencies to events with greater rainfall reduction in the cool half of the year. Despite this shift, we also find a significant decrease in the number of cold extremes occurring during droughts, and an increase in hot extremes. Droughts in New England have been associated with a greater than average frequency of cold nights and frost days, but this relationship has weakened over recent decades. Conversely, they are generally associated with a greater than average frequency of hot days, a relationship that has increased over time. The Tinderbox Drought was the second-most extreme meteorological drought for New England in terms of rainfall deficit and drought severity, and was associated with the highest number of extreme warm temperature events. The new drought climatology for New England can now be used to provide regional drought information for decision makers and the community.

Abstract:

To study and monitor the Sun and its atmosphere, various space missions have been launched in the past decades. With rapid improvement in technology and different mission requirements, the data products are subject to constant change. However, for such long-term studies as solar variability or multi-instrument investigations, uniform data series are required. In this study, we built on and expanded the instrument-to-instrument translation (ITI) framework, which provides unpaired image translations. We applied the tool to data from the Extreme Ultraviolet Imager (EUI), specifically the Full Sun Imager (FSI) on Solar Orbiter and the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO). This approach allowed us to create a homogeneous dataset that combines the two extreme ultraviolet (EUV) imagers in the 174/171 Å and 304 Å channels. We demonstrate that ITI is able to provide image calibration between Solar Orbiter and SDO EUV imagers, independent of the varying orbital position of Solar Orbiter. The comparison of the intercalibrated light curves derived from 174/171 Å and 304 Å filtergrams from EUI and AIA shows that ITI can provide uniform data series that outperform a standard baseline calibration. We evaluate the perceptual similarity in terms of the Fréchet inception distance, which demonstrates that ITI achieves a significant improvement of perceptual similarity between EUI and AIA. The study provides intercalibrated observations from Solar Orbiter/EUI/FSI with SDO/AIA, enabling a homogeneous dataset suitable for solar cycle studies and multi-viewpoint investigations.