Tree rings of Scots pine (Pinus sylvestris L.) as a source of information about past climate in northern Poland

Scots pine (Pinus sylvestris) is a very common tree in Polish forests, and therefore was widely used as timber. A relatively large amount of available wood allowed a long-term chronology to be built up and used as a source of information about past climate. The analysis of reconstructed indexed values of mean temperature in 51-year moving intervals allowed the recognition of the coldest periods in the years 1207–1346, 1383–1425, 1455–1482, 1533–1574, 1627–1646, and 1694–1785. The analysis of extreme wide and narrow rings forms a complementary method of examining climatic data within tree rings. The tree ring widths, early wood and late wood widths of 16 samples were assessed during the period 1581–1676. The most apparent effect is noted in the dry summer of 1616. According to previous research and our findings, temperature from February to March seems to be one of the most stable climatic factors which influenced pine growth in Poland. Correlation coefficients in the calibration and validation procedure gave promising results for temperature reconstruction from the pine chronology

The last millennium climate change in Northern Poland derived from well temperature profiles, tree-rings and instrumental data

In order to reconstruct the air temperature variations in Northern Poland for the last millennium observational and proxy (tree-ring widths) data were used. For the first time the ground surface temperature (GST) for Northern Poland was reconstructed based on geothermal data (well temperature profiles). A general warming trend is observed for both the GSTH (GST Histories) derived from geothermal data and instrumental data, in particular, for the last 200 years

Temperature changes in Poland from the 16th to the 20th centuries

A standardized tree-ring width chronology of the Scots pine (Pinus sylvestris L.) along with different types of documentary evidence (e.g. annals, chronicles, diaries, private correspondence, records of public administration, early newspapers) have been used to reconstruct air temperature in Poland. The ground surface temperature (GST) history has been reconstructed based on the continuous temperature logs from 13 wells, using a new method developed recently by Harris and Chapman (1998; Journal of Geophysical Research 103: 7371–7383) which is compared with the functional space inversion (FSI) method applied to all available Polish temperature–depth profiles analysed before. Response function calculations conducted for trees growing in Poland (except in mountainous regions) reveal a statistically significant correlation between the annual ring widths of the Scots pine and the monthly mean air temperatures, particularly from February and March, but also from January and April. Therefore, it was only possible to reconstruct the mean January–April air temperature. The following periods featured a warm late winter/early spring: 1530–90, 1656–70 (the warmest period), 1820–50, 1910–40, and after 1985. On the other hand, a cold January–April occurred in the following periods: 1600–50, 1760–75, 1800–15, 1880–1900, and 1950–80. Reconstructions of thermal conditions using documentary evidence were carried out for winter (December–February) and summer (June–August) from 1501 to 1840 and, therefore, their results cannot be directly compared with reconstructions based on tree-ring widths. Winter temperatures in this period were colder than air temperature in the 20th century. On the other hand, ‘historical’ summers were generally warmer than those occurring in the 20th century. Such situations dominated in the 16th and 17th centuries, as well as at the turn of the 18th and 19th centuries. Throughout almost the entire period from 1501 to 1840, the thermal continentality of the climate in Poland was greater than in the 20th century. GST reconstructions show that its average pre-instrumental level (1500–1778) is about 0.9–1.5 °C lower than the mean air temperature for the period 1951–81. Lower amplitude of GST warming (0.9 ± 0.1 °C) results from the individual and simultaneous inversions of well temperature data using the FSI method. A very good correspondence of the results has been found between series of annual mean GSTs from the FSI method and mean seasonal air temperatures reconstructed using documentary evidence

Electromagnetic Interference Characterization and Metrology Support Using PXIe System

Electromagnetic compatibility (EMC) is a critical consideration when designing zonal power distribution systems. Managing the electromagnetic energy, both intentional and unintentional, is vital to ensure minimal interference among components of the system. The interference(EMI) is quantified through experiment wherein specific test setups must be developed depending on the equipment under test (EUT). These setups are also governed by particular standards depending on the application which, in this case, is US Navy shipboard applications. Therefore, the governing standards in this project are set forth by the Department of Defense. The test setup includes a system of line impedance stabilization networks (LISN) along with the EUT. Each LISN is utilized to create a known electrical impedance between the source and EUT which enables EMI measurements. In the context of shipboard applications, the LISN’s are meant to simulate the impedance resulting from other components on the ship. The EUT in this setup is a power conversion module comprised of SiC (silicon carbide) MOSFET’s (switches) which have more ideal properties allowing them to dissipate energy more efficiently and subsequently operate at higher frequencies. These higher frequencies result in different EMI characterizations which can be analyzed through this test setup