Václav Bucha

Geomagnetic forcing of changes in climate and in the atmospheric circulation

Abstract Common features in records of solar and geomagnetic activity as well as of climatic parameters can be observed. High correlation coefficients were found between geomagnetic activity, the sea level atmospheric pressure and the surface air temperature, occurring with a positive sign in the middle and southern Europe, in the south-eastern part of North America and in the western Atlantic but with a negative sign in the northern Atlantic and Canada. In the hypothesis proposed here for explaining Sun-weather relations, downward winds following the geomagnetic storm onset are generated in the polar cap of the thermosphere and penetrate to the stratosphere and troposphere, where the atmospheric response can be observed as a sudden increase of pressure and temperature. The subsidence effects along the northern margin of the subpolar high pressure areas (mainly the Siberian high) are accelerated and strong eastward winds participate in the intensification of the northern jet stream and in the successive zonalization of flow in mid-latitudes. It is shown that at a time of low geomagnetic activity planetary waves with large amplitudes prevail in the northern hemisphere due to the orographic effect of the Rocky Mountains and Greenland. On the other hand, at a time of high geomagnetic activity, an intensification of the winds can be observed not only in the thermosphere but also in the troposphere. A strong northern jet stream participates in the intensification of the westerly zonal flow and in the increase of temperature successively in the eastern part of North America, in Europe and northern Asia. These relations are clearly detectable not only in monthly averages of the pressure and temperature distribution but also in the daily variations of atmospheric circulation. The results enable us to test a causal link of the Sun-weather processes, to explain strong interannual climate and weather changes in several key regions of the northern hemisphere, mainly in winter, and to study possible causes of the North Atlantic Oscillation. The results obtained contribute also to the study of the occurrence of long-term cyclic changes which were observed both in solar and geomagnetic activity and temperature T, as well as in the radioactive Δ14C, and have a similar trend. A composite curve was suggested by summing up sinusoidal curves with periods 70, 200, 800 and 2400 years roughly representing changes of all three mentioned parameters (aa, T and Δ14C) during the past 1600 years and their probable trend for the next 800 years. The results seem to imply that the global warming could be slowed down in next decades, because the natural component influencing the increase of temperature in the 20th century will most probably decrease in the next century due to the weaker external geomagnetic forcing which was suggested to modify natural meteorological processes.

Variations of the geomagnetic field, the climate and weather

SummaryUsing palaeomagnetic investigations of sedimentary rocks and particularly lake sediments, changes of the geomagnetic field and geomagnetic poles were determined over a period of the last 40 000 years. The correlations between geomagnetic, climatic and meteorological phenomena were investigated with the object of demonstrating the function of the geomagnetic pole and changes in its positions in forming the climate and weather. A tentative model has been proposed to enable the causes of the generation of glacial and interglacial periods, as well as the causes effecting changes of weather to be explained. The possibilities of man-made meliorations of the climate in certain regions are also discussed.

Resonance frequencies in the sun's motion

РезюмеБыло вычuсленоnоложенuе Солнца омноцuельно барыценмра цолнечноŭ сuсмемы ¶rt;ля начала каж¶rt;огого¶rt;а uз бременного ря¶rt;а ¶rt;лuноŭ 3100 лем u c¶rt;елангармонuческuŭ аналuз nарамемров ¶rt;вuженuŭ Солнца вокруг барыuенмра.SummaryThe position of the Sun with respect to the gravity centre of the Solar System for the beginning of every year of a 3100 — year time series was determined and the harmonic analysis of the parameters of the Suns motion about the gravity centre was carried out.

Direct relations between solar activity and atmospheric circulation, its effect on changes of weather and climate

РезюмеНa основе обрaбоmкu совокуnносmuгеомaгнumных u меmеорологuческuх ¶rt;aнных nокaзaно, чmо nовышенuе корnускулярноŭ рa¶rt;uaцuu nроявляющееся вгеомaгнumноŭ aкmuвносmu u соnровож¶rt;aемое усuленным nронuкновенuем элекmронов в сре¶rt;нюю amмосферу u сmрamосферу, вознuкновенuем зamорможенноŭ рa¶rt;uaцuu u uонных скоnленuŭ нa высоmaх около 15 км, nрuво¶rt;um к nоmеnленuю u nовышенuю amмосферного ¶rt;aвленuя в сmрamосфере u mроnосфере. Оmмеченные эффекmы nрuво¶rt;яm к неnосре¶rt;сmвенному nовышенuю mемnерamуры u ¶rt;aвленuя maкже нa уровне 500 мбaр в aврорaльном овaле u к nерехо¶rt;у мерu¶rt;uонaльного muna в зонaльныŭ mun amмосферноŭ цuркуляцuu. Резульmamы nо¶rt;mверж¶rt;ённые сmamuсmuческоŭ обрaбоmкоŭ ¶rt;aнных nокaзывaюm, чmо nрuве¶rt;ённые uзмененuя ¶rt;вuженuя воз¶rt;ушных мaсс nрuво¶rt;яm к явным uзмененuям mемnерamуры u ¶rt;aвленuя в Евроnе u Северноŭ Амерuке u сnособсmвуюm внезanным вmорженuям aркmuческого воз¶rt;ухa nрu nонuженноŭ корnускулярноŭ рa¶rt;uaцuu u внезanным нaгревaм сmрamосферы nрu nовышенноŭ корnускулярноŭ рa¶rt;uaцuu. Нa основе nре¶rt;ложенного мехaнuзмa можно ¶rt;обыmься maкже объясненuя короmко- u ¶rt;олговременных uзмененuŭ клuмama u nрuчuн вознuкновенuя u чере¶rt;овaнuя ле¶rt;нuковых u межле¶rt;нuковых nерuо¶rt;ов.

Relation between Northern Hemisphere winter temperatures and geomagnetic or solar activity at different QBO phases

Abstract In our previous work a dominant coupling was shown between solar and geomagnetic activity, and surface air temperature of the QBO-west and east phases, respectively. The aim of the present study is to define ‘typical’ regions of positive and negative deviations from the long-term temperature average, to determine their magnitude and to find the conditions under which such a ‘typical’ distribution of temperature fields occurs.

Changes in the geomagnetic field and solar wind — causes of changes of climate and atmospheric circulation

SummaryThe analyses of various types of geomagnetic and atmospheric manifestations have disclosed certain associations. The agreement in the occurrence of the increased spectral densities as regards geomagnetic activity and the variations of atmospheric pressure over the geomagnetic pole proves the relation between their periodicities. The results imply that the changes in the intensity of corpuscular radiation, indicated by geomagnetic activity, affect the pressure patterns over the geomagnetic pole and polar region significantly, so that a pronounced modification of the general circulation may take place, as shown schematically in Figs 14a,b.

Mechanism of solar-terrestrial relations and changes of atmospheric circulation

SummaryAs a result of investigating the relations between the variations of geomagnetic activity and meteorological factors [1, 2] a mechanism of solar-terrestrial relationships and a model of the changes of atmospheric circulation in the Northern Hemisphere are proposed; this provides an explanation of the causes of the fluctuation of the climate, of dry and cold periods and differing vegetation conditions in various years in dependence on the intensity of geomagnetic activity.

Geomagnetic forcing and climatic variations in Europe, North America and in the Pacific Ocean

Abstract The influence of geomagnetic forcing on the variability of key climatic systems including the North Atlantic Oscillation, fluctuations of the temperature in Europe and North America, variability of the rainfall in the Asian Monsoon region, and the El Nino-Southern Oscillation (ENSO) in the Pacific region was studied to identify possible causes. Statistically significant correlation coefficients were found between geomagnetic activity, the sea-level atmospheric pressure (s.l.p.) and temperature. Enhanced geomagnetic forcing is shown to lead to the intensification of the westerly zonal flow and to fluctuations of temperature in Europe, in the United States, and northern Asia. Correlation coefficients that were found between changes in geomagnetic activity, the All India Rainfall Index and ENSO suggest that the increase of geomagnetic activity in April also strengthens the zonal flow even in the Southern Hemisphere in the southern fall and winter. Strong southerly winds and the cross-equatorial flow extend across the entire Indian Ocean leading to the above-normal monsoon rainfall in India in summer. At a time of decreased geomagnetic activity in April, the Australian high intensifies and the southerly cross-equatorial flow in the Indian Ocean is much weaker. The monsoon rainfall is deficient and an El Nino (Warm event) is usually observed in the Pacific Ocean.

Dynamic manifestations of the geomagnetic field in the Quaternary continental sediments of Czechoslovakia

SummaryThe paper brings a brief geological asessment of the sedimentational cycles, analyses the methods of collection and investigation of samples and the representativeness of the results obtained. Problems of magnetic cleaning and the types of demagnetization curves investigated are discussed. The continuous nature of the variations of the magnetic declination, inclination and remanent magnetization, determined by palaeomagnetic investigation of Quaternary sediments, is also discussed. The conclusion contains the principal facts about the dynamics of the geomagnetic field in the Quaternary and points out the possibility of applying them to the theory of the geomagnetic field, as well as to geological correlations.

Archaeomagnetic research into the total geomagnetic field intensity and its changes in Czechoslovakia

РезюмеВ настоящей работе дискутированы свойства остаточного намагничивания археологических объектов из обожженой глины и метод последовательных двойных нагревов позволяуший определить абсолютную величину вектора геомагнитного поля в прошлом. Основная часть работы посвящена археомагнитному исследованию образцов Чехословакии и дискуссии полученных данных. На основе лабораторной обработки археологических образцов разного возраста начиная с 4400 г. до н. з. до современности была определена кривая изменения абсолютного значения геомагнитного поля; результаты приведены вместе с данными для отдельных образцов на рис. 7. Большое внимание в работе уделяется лабораторной преверке метода. При помощи приведенного метода двохных нагревов были исследованы образцы из глины по составу близкой археологическим образцам. Сначала были произведены нагревы отдельных образцов до различных температур (300°, 400°, 450°, 500°, 670°) и полученные кривые размагничивания, намагничивания и „опрокинутая” кривая между собой сравнены. Оказалось, что для определения интенсивности геомагнитного поля являются пригодными те археологические образвы, которые были обожжены до температур выше чем 300°. Для определения козффициентак=Фдр/Флаб можно нспользовать только тот участок кривых, вдоль которого с начала кривая размагничивания и опрокинутая кривая согласуются. В случае удаления приведенных двух кривых обнаруживается, что температура первоначального обожжения была ниже температур, при которых кривые взаимно сильно отличаются друг от друга (рис. 8а, в).Далее в работе дискутирована возможность применения полученных археомагнитных результатов, для археологической датировки.Временное распределение геомагнитного поля на земной поверхности, как вытекает из рис. 10 характеризующего временной ход геомагнитных элементовD, I, F в геомагнитных мировых обсерваториях представляет очень сложную картину. Также археомагнитные данные на более удаленных местах могут значительно взаимно отличаться, вследствии влияния континентальных геомагнитных аномалий. Поэтому более подробное археомагнитное исследование может обнаружить новые закономерности по остаточному магнитному полю Земли.