Climate field completion via Markov random fields – Application to the HadCRUT4.6 temperature dataset
"Surface temperature is a vital metric of Earth’s climate state, but is incompletely observed in both space and time: over half of monthly values are missing from the widely used HadCRUT4.6 global surface temperature dataset. Here we apply GraphEM, a recently developed imputation method, to construct a spatially complete estimate of HadCRUT4.6 temperatures. GraphEM leverages Gaussian Markov random fields (aka Gaussian graphical models) to better estimate covariance relationships within a climate field, detecting anisotropic features such as land/ocean contrasts, orography, ocean currents and wave-propagation pathways.[...]"
Source: AMS- American Meteorological Society
Authors: Adam Vaccaro et al.
11 - Impacts of strong warm ocean currents on development of extratropical cyclones through the warm and cold conveyor belts: A review
"Recent high-resolution observations and numerical simulations have revealed active roles of the ocean in the mid-latitude climate system. In this chapter, we review recent studies on the topic especially focusing on roles of strong oceanic warm currents and associated sea surface temperature (SST) frontal structures in the development of extratropical cyclones, which can cause extreme rainfall/snowfall. Speed of the warm strong ocean currents such as the Kuroshio/Kuroshio Extension and activities of associated mesoscale eddies have strong influence on SST and its meridional[...]"
Source: Science Direct
Authors: Hidetaka Hirata et al.
Impact of mid-glacial ice sheets on deep ocean circulation and global climate
"This study explores the effect of southward expansion of Northern Hemisphere (American) mid-glacial ice sheets on the global climate and the Atlantic Meridional Overturning Circulation (AMOC) as well as the processes by which the ice sheets modify the AMOC. For this purpose, simulations of Marine Isotope Stage (MIS) 3 (36 ka) and 5a (80 ka) are performed with an atmosphere–ocean general circulation model. In the MIS3 and MIS5a simulations, the global average temperature decreases by 5.0 and 2.2 ∘C, respectively, compared with the preindustrial climate simulation. The AMOC weakens by 3 % in MIS3, whereas it strengthens[...]"
Source: EGU-European Geosciences Union
Authors: Sam Sherriff-Tadano et al.
The warmer the ocean surface, the shallower the mixed layer. How much of this is true?
Ocean surface warming is commonly associated with a more stratified, less productive, and less oxygenated ocean. Such an assertion is mainly based on consistent projections of increased near-surface stratification and shallower mixed layers under global warming scenarios. However, while the observed sea surface temperature (SST) is rising at midlatitudes, the concurrent ocean record shows that stratification is not unequivocally increasing nor is MLD shoaling.
Source: Journal of Geophysical Research: Oceans
Authors: R. Somavilla, C. González-Pola, J. Fernández-Diaz
Read the full article here.