Современное прочтение истории ледниковых циклов плейстоцена

One of the, Glaciological descriptions of Greenland and Antarctica were among the most outstanding events in the geographical investigations of the Earth, made in the 20th century. They have shown that glaciations, traces of which were found in Europe and North America in the first half of the 19th century, waxed and waned during the Pleistocene repeatedly and were synchronous with the expansions and reductions of the Antarctic ice sheet. Further analyses of the sea-bed sediments confirmed the fact of such synchronicity, and revealed that the durations of the Pleistocene glacial cycles (on the order of one hundred thousand years) were significantly longer then approximately forty thousand years alternations of the warm and cold climate conditions during the preceding Pliocene. In this paper, using wavelets, and methods of the theory of the nonlinear dynamical systems, patterns of the Pleistocene’s and Pliocene’s cyclic variations of climate are compared with each other, to understand the mechanisms which can be responsible for their excitation and evolution. Гляциологические описания Гренландии и Антарктиды – одни из наиболее выдающихся событий в географических исследованиях Земли ХХ в. Эти описания показали, что покровные оледенения, следы которых обнаружены в Европе и Северной Америке ещё в первой половине XIX в., возникали и исчезали в плейстоцене многократно и при этом были синхронными с разрастаниями и сокращениями Антарктического ледникового щита. Последующие анализы донных океанических отложений подтвердили факт синхронности и позволили установить, что по продолжительности (порядка 100 тыс. лет) плейстоценовые ледниковые циклы были существенно больше примерно 40-тысячелетних чередований потеплений и похолоданий климата в предшествующем плиоцене. В данной статье с помощью вейвлетного анализа и методами теории нелинейных динамических систем сравниваются структуры плейстоценовых и плиоценовых циклических вариаций климата и устанавливаются механизмы, ответственные за их возбуждение и эволюцию.

Исследование разномасштабных взаимосвязей между изменениями приземной температуры воздуха и концентрации СО2 в атмосфере

A concept of the anthropogenic origin of the current global climate warming assumes that growth of concentration of the atmospheric carbon dioxide and other greenhouse gases is of great concern in this process. However, all earlier performed analyses of the Antarctic ice cores, covering the time interval of several glacial cycles for about 1 000 000 years, have demonstrated that the carbon dioxide concentration changes had a certain lag relative to the air temperature changes by several hundred years during every beginning of the glacial terminations as well as at endings of interglacials. In contrast to these findings, a recently published careful analysis of Antarctic ice cores (Parrenin et al., 2013) had shown that both, the carbon dioxide concentration and global temperature, varied almost synchronously during the transition from the last glacial maximum to the Holocene. To resolve this dilemma, a special technique for analysis of the paleoclimatic time series, based on the wavelets, had been developed and applied to the same carbon dioxide concentration and temperature time series which were used in the above paper of Parrenin et al., 2013. Specifically, a stack of the Antarctic δ18O time series (designated as ATS) and the deuterium Dome C – EPICA ones (dD) were compared to one another in order to: firstly, to quantitatively estimate differences between time scales of these series; and, secondly, to clear up the lead–lag relationships between different scales variations within these time series. It was found that accuracy of the mutual ATS and dD time series dating lay within the range of 80–160 years. Perhaps, the mutual dating of the temperature and carbon dioxide concentration series was even worse due to the assumed displacement of air bubbles within the ice. It made us to limit our analysis by the time scales of approximately from 800 to 6000 years. But it should be taken into account that any air bubble movement changes the time scale of the carbon dioxide series as a whole. Therefore, if a difference between variations in any temperature and the carbon dioxide time series is found to be longer than 80–160 years, and if these variations are timescale‑dependent, it means that the bubble displacements are not essential, and so these advancing and delays are characteristic of the time series being compared. Our wavelet‑based comparative and different‑scale analysis confirms that the relationships between the carbon dioxide concentration and temperature variations were essentially timescale‑dependent during the transition from the last glacial maximum to the Holocene. The carbon dioxide concentration variations were ahead of the temperature ones during transition from the glacial maximum to the Boelling – Alleroud warming as well as from the Young Drias cooling to the Holocene optimum. However, the temperature variations were ahead during the transition from the Boelling – Alleroud warming to the Young Drias cooling and during the transition from the Holocene optimum to the present‑day climate.С целью выяснения причин современного изменения климата сопоставляются многомасштабные изменения средней глобальной приземной температуры воздуха и концентрации СО2 в атмосфере по данным антарктических ледниковых кернов. Рассматривается период перехода от максимума последнего оледенения к голоцену. Для этого разработана специальная техника кроссвейвлетного анализа временных рядов. Установлено, что соотношения лидирования – запаздывания между изменениями температуры и концентрации СО2 существенно зависели на рассматриваемом временнóм интервале от временных масштабов и фаз ускорения или замедления изменений сравниваемых характеристик

Observability of planetary waves and their predictability in the ECMWF H500 forecasts

The problem of a hard contradiction between limited possibilities of meteorological observations and uncontrolled complication of the present-day weather forecasting models, and its consequences for the planetary wave predictability are considered with examples from the ECMWF short- and medium-range H500 forecasts for the Northern Hemisphere. A supposition is voiced that this problem adds difficulties to the weekly predictability limit overcoming

A modern interpretation of the history of the Pleistocene glacial cycles

One of the, Glaciological descriptions of Greenland and Antarctica were among the most outstanding events in the geographical investigations of the Earth, made in the 20th century. They have shown that glaciations, traces of which were found in Europe and North America in the first half of the 19th century, waxed and waned during the Pleistocene repeatedly and were synchronous with the expansions and reductions of the Antarctic ice sheet. Further analyses of the sea-bed sediments confirmed the fact of such synchronicity, and revealed that the durations of the Pleistocene glacial cycles (on the order of one hundred thousand years) were significantly longer then approximately forty thousand years alternations of the warm and cold climate conditions during the preceding Pliocene. In this paper, using wavelets, and methods of the theory of the nonlinear dynamical systems, patterns of the Pleistocene’s and Pliocene’s cyclic variations of climate are compared with each other, to understand the mechanisms which can be responsible for their excitation and evolution