Near-Surface Biases in ERA5 Over the Canadian Prairies
Frontiers in Environmental Science 7 (2019)
Abstract:
We quantify the biases in the diurnal cycle of air temperature in ERA5, using hourly climate station data for four stations in Saskatchewan, Canada. Compared with ERA-Interim, the biases in ERA5 have been greatly reduced, and show no differences with snow cover. We compute fits to the ERA5 mean air temperature biases based on ERA5 effective cloud albedo. They can be used to improve the ERA5 diurnal cycle of air temperature for modeling agricultural processes. Diurnally, ERA5 has a negative wind speed bias, which increases quasi-linearly with wind speed, and is greater in the daytime than at night. We evaluate ERA5 precipitation against the original climate station precipitation data, and a second generation adjusted precipitation dataset by Mekis and Vincent (2011). For the warm season, ERA5 has a high bias of 8 ± 9% above the Mekis dataset. ERA5 is −22 ± 7% below the Mekis estimate in winter, suggesting that their correction with snow may be too large. It is likely that the ERA5 precipitation bias is small, which is encouraging for agricultural modeling. Data from a BSRN site near Regina shows that the biases in the downwelling shortwave and longwave radiation estimates in ERA5 are small, and have changed little from ERA-Interim. We show that the annual cycle of the Saskatchewan surface energy and water budgets in ERA5 are realistic. In particular the damping of extremes in summer precipitation by the extraction of soil water is comparable in ERA5 to our earlier observational estimate based on gravity satellite data.Proton-driven plasma wakefield acceleration in AWAKE.
Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 377:2151 (2019) 20180418
Abstract:
In this article, we briefly summarize the experiments performed during the first run of the Advanced Wakefield Experiment, AWAKE, at CERN (European Organization for Nuclear Research). The final goal of AWAKE Run 1 (2013-2018) was to demonstrate that 10-20 MeV electrons can be accelerated to GeV energies in a plasma wakefield driven by a highly relativistic self-modulated proton bunch. We describe the experiment, outline the measurement concept and present first results. Last, we outline our plans for the future. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.A compact electron injector for the EIC based on plasma wakefields driven by the RHIC-EIC proton beam
ArXiv 1907.01191 (2019)
A compact electron injector for the EIC based on plasma wakefields driven by the RHIC-EIC proton beam
Sissa Medialab Srl (2019) 219
FLASHForward: plasma wakefield accelerator science for high-average-power applications.
Philosophical Transactions of the Royal Society A Royal Society 377:2151 (2019) Article:20180392