Results 141 to 150 of about 49,347 (211)
Quarterly Journal of the Royal Meteorological Society, EarlyView.The climatological‐error covariance matrix used in three‐dimensional variational data assimilation (3DVar) provides smooth and isotropic increments spread to long distances. In contrast, three‐dimensional ensemble variational data assimilation (3DEnVar) with a purely ensemble‐error covariance matrix provides inhomogeneous increments and contains the ...
Kaushambi Jyoti +3 more
wiley +1 more source
Quarterly Journal of the Royal Meteorological Society, EarlyView.We document for the first time how the assimilation of CS2SMOS observations improves the model representation of Arctic sea‐ice thickness (SIT) and its variability: biases are reduced (top row), while excessive variability in the Beaufort Sea and lack of variability in the ice pack are both corrected (bottom row).
Jiping Xie +3 more
wiley +1 more source
Forecast‐Error Diagnostics in Neural Weather Models
Quarterly Journal of the Royal Meteorological Society, EarlyView.Deep learning weather prediction models enable efficient forecast‐error diagnostics through auto‐differentiation and low computational cost. We apply grid‐point relaxation and gradient‐based error sensitivity to identify key forecast‐error sources. Results show that medium‐range forecasts in the midlatitudes benefit most from relaxing the stratosphere ...
Uroš Perkan +2 more
wiley +1 more source
The relationship between equatorial wave interaction and heavy rainfall in Southeast Asia
Quarterly Journal of the Royal Meteorological Society, EarlyView.This study examines the statistical relationship between co‐occurring equatorial waves and heavy rainfall in Southeast Asia. Heavy rainfall is more closely related to combined wave activity than to individual waves in many regions of Southeast Asia. The figure shows GPM–IMERG rainfall (shading) and ERA5 850‐hPa winds (vectors) composited on days when ...
Samantha Ferrett +7 more
wiley +1 more source
Observations and numerical simulations of a valley‐exit wind in the Alpine Bolzano basin
Quarterly Journal of the Royal Meteorological Society, EarlyView.The evolution and spreading of the nocturnal valley‐exit wind flowing from the Isarco Valley into the Bolzano basin, in the Italian Alps, are found to be influenced by the basin temperature stratification. Measurements and high‐resolution simulations show that a cold‐air pool favors an upward trajectory of the flow at the exit of the valley.
Federica Gucci +4 more
wiley +1 more source
Epistemic and aleatoric uncertainty quantification in weather and climate models
Quarterly Journal of the Royal Meteorological Society, EarlyView.Aleatoric and epistemic uncertainties over time on weather and climate time‐scales, estimated through ensembles that sample aleatoric and epistemic uncertainty using Bayesian neural networks for parameterisations in the Lorenz 1996 model. The spread shows the 16th and 84th percentiles.
Laura A. Mansfield +1 more
wiley +1 more source
Quarterly Journal of the Royal Meteorological Society, EarlyView.Quasi‐stationary linear precipitation systems (QSLPSs) are a major cause of heavy rainfall in Japan, persisting over the same region for more than five hours. This study demonstrates that entraining convective available potential energy (E‐CAPE), which accounts for environmental air entrainment during parcel ascent, more accurately characterises the ...
Eigo Tochimoto +5 more
wiley +1 more source
Quarterly Journal of the Royal Meteorological Society, EarlyView.This study reveals that the combined effects of the North Atlantic Oscillation (NAO) and anomalous Indo‐Pacific Walker circulation on the excitation of the wave train along the wintertime subtropical jet strongly depend on their phase combination. Their impacts interfere constructively or destructively over South Asia, leading to notable differences in
Yuki Asazuma +2 more
wiley +1 more source
Ensemble reliability and the signal‐to‐noise paradox in ECMWF subseasonal forecasts
Quarterly Journal of the Royal Meteorological Society, EarlyView.We derive a general expression for the ratio of predictable components (RPC) in terms of correlation, spread–error ratio, and total variance ratio. Physical constraints on the admissible solutions (i.e., real‐valued and non‐negative variances) provide a mechanism to identify statistically paradoxical sample combinations of reliability and correlation ...
Christopher D. Roberts, Frederic Vitart
wiley +1 more source
Quarterly Journal of the Royal Meteorological Society, EarlyView.This large‐eddy simulation study on pyroconvection shows that the added value from resolving the mesoscale explicitly is found in the timing of pyrocumulus formation and circulation changes. The circulation of the convective plume itself is not substantially different between the simulations. Abstract Extreme wildfire events are characterised by strong
Koen van der Aa +4 more
wiley +1 more source