Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Citation Impact of Open Access Publications by Scholars in the Middle East

<p>Nikesh Narayan & Yrjo Lappalainen presented "Citation Impact of Open Access Publications by Scholars in the Middle East" during the 2023 Annual Forum for Open Research in Abu Dhabi, UAE. </p&gt

On sea level change in the North Sea influenced by the North Atlantic Oscillation: local and remote steric effects

In this study, contributions of both local steric and remote baroclinic effects (i.e., steric variations external to the region of interest) to the inter-annual variability of winter sea level in the North Sea, with respect to the North Atlantic Oscillation (NAO), for the period of 1953–2010 are investigated. On inter-annual time scales in this period, the NAO is significantly correlated to sea level variations in the North Sea only in the winter months (December–March), while its correlation to sea temperature over much of the North Sea is only significant in January and February. The discrepancy in sea level between observations and barotropic tide and surge models forced by tides and local atmospheric forcing, i.e., local atmospheric pressure effects and winds, in the present study are found to be consistent with previous studies. In the North Sea, local thermosteric effects caused by thermal expansion play a minor role on winter-mean NAO related sea level variability compared with atmospheric forcing. This is particularly true in the southeastern North Sea where water depths are mostly less than 25 m. Our calculations demonstrate that the discrepancy can be mostly explained by remote baroclinic effects, which appear as water mass exchanges on the continental shelf and are therefore only apparent in ocean bottom pressure. In the North Sea, NAO related sea level variations seem to be a hybrid of barotropic and baroclinic processes. Hence, they can only be adequately modelled with three-dimensional baroclinic ocean models that include contributions of baroclinic effects and large-scale atmospheric forcing external to the region of interest

Assessment of the Met Office Global Coupled model version 5 (GC5)configurations

GC5 is the latest global coupled configuration which is a combination of Global Atmosphere and Land (GAL9) and Global Ocean and Sea Ice (GOSI9). GAL9 includes over 26 science tickets that cover changes to almost all areas of global model science, including several enhancements to the 6A convection scheme, latent heating in the gravity wave drag scheme, ‘fountain buster’ scheme which adds improvements to advection conservation in conditions of near-grid-scale convergence, bimodal cloud initiation and dust dependent ice-nucleation temperature. GOSI9 is built on the NEMO 4.0.4 ocean model and a new sea ice model SI3. This includes a new equation of state (TEOS-10), 4th order tracer advection, adaptive-implicit vertical advection and Southern Ocean tuning. Important model improvements in global temperature and winds, subtropical jet, monsoon processes over India and Maritime Continent and their diurnal cycle in convection were noted. Most aspects of processes over Africa were also notably improved. Southern Ocean biases continue to reduce in GC5 as a result of the Southern Ocean package including the Antarctic Sea ice area. At NWP scales, significant improvements in the tropical temperature at 850hPa and precipitation SEEPs score at all lead times were achieved. In addition, the tropical cyclone track and intensity are significantly better in GC5 compared to GC4. There are aspects where the model has slightly degraded such as the MJO, Indian Ocean SSTs and winds, biases over NE South America, western Pacific high in northern hemisphere summer and European blocking in northern hemisphere summer. These degradations require more detailed investigations. Degradations to NWP performance at higher resolution also need to be investigated before operational implementation but will require minimal adjustments. While the N216 GC5 model is acceptable for release as the physical model configuration, further work is being undertaken in the climate science community to address the cold bias in GC5 N96ORCA1 configuration. The resulting GC5 configurations for a wider range of climate applications will be documented in a separate paper. Unlike previous configurations, with the aim of getting an early understanding of the impact of GC5, tests were carried out on the UK convective-scale ensemble system, MOGREPS-UK. The results assessed here show degradation in the skills of 10m-wind and clouds in Boreal summer, but improvements in the spatial skill of the precipitation forecasts. The results also show a decrease in the ensemble spread with GC5 along with a slight increase in error and this is being investigated