Erroneous arctic temperature trends in the ERA-40 reanalysis: A closer look

© Copyright 2011 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act September 2010 Page 2 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or [email protected] reanalyses can be useful tools for examining climate variability and change; however, they must be used cautiously because of time-varying biases that can induce artificial trends. This study explicitly documents a discontinuity in the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) that leads to significantly exaggerated warming in the Arctic mid- to lower troposphere, and demonstrates that the continuing use of ERA-40 to study Arctic temperature trends is problematic. The discontinuity occurs in 1997 in response to refined processing of satellite radiances prior to their assimilation into the reanalysis model. It is clearly apparent in comparisons of ERA-40 output against satellite-derived air temperatures, in situ observations, and alternative reanalyses. Decadal or multidecadal Arctic temperature trends calculated over periods that include 1997 are highly inaccurate, particularly below 600 hPa. It is shown that ERA-40 is poorly suited to studying Arctic temperature trends and their vertical profile, and conclusions based upon them must be viewed with extreme caution. Consequently, its future use for this purpose is discouraged. In the context of the wider scientific debate on the suitability of reanalyses for trend analyses, the results show that a series of alternative reanalyses are in broad-scale agreement with observations. Thus, the authors encourage their discerning use instead of ERA-40 for examining Arctic climate change while also reaffirming the importance of verifying reanalyses with observations whenever possibl

Концепция устройства и энергетический потенциал парокомпрессионного теплохладоснабжения на основе бинарного низкотемпературного источника

The combined use of low-potential soil heat and air flows in heat pump heat supply systems allows for its regulated redistribution in the processes of customers’ consumption. Herewith, the intensity of energy extraction by the soil heat exchanger decreases, excess heat is accumulated with a decrease in the depth of wells, and the costs of installing and operating probe heat exchangers are also reduced. An improved version of the conceptual arrangement of a vapor compression system for heat and cool supply of buildings based on the integrated heat of soil and ventilation air has been developed. Its distinguished features are the possibility of automatic redistribution of generated heat flows in the subsystems of customers’ heat consumption and accumulation of excess part in the soil mass. When the system is operating in the warm season with the extraction of heat only for hot water supply, there is a more intensive accumulation of excess heat of the ventilation air in the soil mass, which restores its temperature in the accumulation mode for further use with the coming of the heating period. Multifactor analytical dependences of the heat flows of the main equipment have been established, taking into account the initial parameters and operating conditions of the structural subsystems for the extraction, transformation and consumption of heat, which are the basis for determining the energy potential of vapor compression heat and cold supply using a binary low-temperature source.Совместное использование низкопотенциальной теплоты грунта и воздушных потоков в теплонасосных системах теплоснабжения позволяет осуществлять ее регулируемое перераспределение в процессах абонентского потребления. При этом снижается интенсивность отбора энергии грунтовым теплообменником, избыточная теплота аккумулируется с уменьшением глубины скважин, а также сокращаются затраты на устройство и эксплуатацию зондовых теплообменников. Разработан усовершенствованный вариант концептуального устройства парокомпрессионной системы теплохладоснабжения зданий на основе интегрированной теплоты грунта и вентиляционного воздуха, отличающийся возможностью автоматического перераспределения генерируемых тепловых потоков в подсистемах абонентского теплопотребления и аккумулирования избыточной части в грунтовом массиве. При работе системы в теплый период года с отбором теплоты только на горячее водоснабжение происходит более интенсивное аккумулирование избыточной теплоты вентиляционного воздуха в грунтовом массиве, который восстанавливает свою температуру в режиме аккумулирования для дальнейшего использования с наступлением отопительного периода. Установлены многофакторные аналитические зависимости тепловых потоков основного оборудования, учитывающие исходные параметры и режимные условия работы структурных подсистем отбора, трансформации и потребления теплоты, которые являются основой для определения энергетического потенциала парокомпрессионного теплохладоснабжения с использованием бинарного низкотемпературного источника.

Monthly precipitation mapping of the Iberian Peninsula using spatial interpolation tools implemented in a Geographic Information System

Premi a l'excel·lència investigadora. Àmbit de les Ciències Socials. 2008In this study, spatial interpolation techniques have been applied to develop an objective climatic cartography of precipitation in the Iberian Peninsula (583,551 km2). The resulting maps have a 200m spatial resolution and a monthly temporal resolution. Multiple regression, combined with a residual correction method, has been used to interpolate the observed data collected from the meteorological stations. This method is attractive as it takes into account geographic information (independent variables) to interpolate the climatic data (dependent variable). Several models have been developed using different independent variables, applying several interpolation techniques and grouping the observed data into different subsets (drainage basin models) or into a single set (global model). Each map is provided with its associated accuracy, which is obtained through a simple regression between independent observed data and predicted values. This validation has shown that the most accurate results are obtained when using the global model with multiple regression mixed with the splines interpolation of the residuals. In this optimum case, the average R2 (mean of all the months) is 0.85. The entire process has been implemented in a GIS (Geographic Information System) which has greatly facilitated the filtering, querying, mapping and distributing of the final cartography