PL
Artykuł, na tle dotychczasowych licznych doświadczeń dotyczących delimitacji Pojezierza Kaszubskiego i jego podziału na mikroregiony fizycznogeograficzne, przedstawia autorską propozycję takiego podziału. W trakcie wydzielania regionów przyjęto kryteria związane z rzeźbą terenu (wysokość n.p.m., spadki terenu i wskaźnik wilgotności terenu) oraz podłożem geologicznym w aspekcie litologii powierzchniowych utworów geologicznych (rodzaje gleb). Wydzielono 78 regionów lito- i hydrogenicznych (w tym dolinnych i rynnowych), które zostały scharakteryzowane z zastosowaniem wybranych metryk dotyczących ich formy i rzeźby. Porównania rezultatów delimitacji z wcześniejszymi jej propozycjami, wskazuje, że na najniższych poziomach regionalizacji fizycznogeograficznej wydzielane powinny być co najmniej dwa poziomy regionów, oprócz mikro-, również nanoregiony, którym bardziej odpowiadają przedstawione w opracowaniu jednostki.
EN
The last version of physical-geographical regionalisation for all Poland (Kondracki 1994) was prepared more than 20 years ago and particular microregionalisation for Eastern Pomerania (Przewoźniak 1985) 30 years ago. During last two decades rose up the knowledge about Polish landscape structure, snowballed the range and accuracy of environmental data, developed methods of digital landscape analysis and direction of physical-geographical regionalisation applications. These arguments validate the necessity for verification of existed regionalisation, particularly landscape division on microregions. This paper presents methodology and application of microregional landscape division for young-glacial areas of Middle Europe on the example of Cassubian Lakeland in Northern Poland (Pomerania), West of Gdańsk urban area. A lot of geographers tried to delimitate Cassubian Lakeland during last 70 years (fig. 1). The first attempts were made by A. Pietkiewicz (1947) and R. Galon (1947). Many versions were prepared by B. Augustowski (1969, 1977, 1979) and J. Kondracki (1964, 1968, 1994) (fig. 2). The most popular version for Gdańsk voivodeship (including Cassubian Lakeland) microregionalisation was introduced by M. Przewoźniak (1985). The last version of regional borders was prepared by M. Kistowski and J. Szydłowski (2015). According to previous studies, author propose microregion delimitation based on two main groups of natural component features: geological formations (lithology of shallow subsurface geological sediments) and relief (form connected with elevation differentiation, slopes and local relief features, described mathematically by topographic wetness index) (fig. 3) and additionally surface water network. The data were acquired from different sources, mainly digital maps in vector and raster forms (topographical, geological, soil, forest maps) corresponded to 1: 10.000 cartographical scale, digital elevation model (1 m accuracy, generalized to 5 m for more fluent digital processing) and Topographical Objects Database from National Geodesy and Cartographic Survey. The original element of proposed methodology was the application of DEM transformations, particularly topographic wetness index (TWI), described relief influence on surface water migration with account of local outflow area, slopes and areas preferable for water accumulation (Beven, Kirkby 1979; Moore, Grayson 1991; Sørensen, Zinko, Seibert 2006). The key for microregions delimitation on young-glacial areas are division on lithogenic (mainly with mineral sediments) and hydrogenic (mainly with organic sediments) landscapes. The author's study showed, that value about 9-10 of topographic wetness index usually divided lithogenic and hydrogenic landscapes (fig. 5). The analysis of 12 types of geological sediments let for more detail microregionalisation and for delimitation of more dense lithogenic microregions not divided by hydrogenic regions (fig. 6). The general rule was accepted, that minimal area of lithogenic microregions is 10 sq. km and hydrogenic - 3 sq. km, but the aberrances is acceptable and the further discussion on minimal region area is necessary. The results of the study showed that Cassubian Lakeland consist of 78 physical-geographical microregions (37 lithogenic and 41 hydrogenic, including 22 valleys and 19 glacial channels). The essential morphometric and relief metrics were showed in table 1 (for every microregion) and table 2 (average for microregion types). The average area of microregion fluctuate from 1,25 sq. km to 284,3 sq. km. The difference between average area of lithogenic (79 sq. km) and hydrogenic (5,6 sq. km) regions are huge (14-fold more). The differences of microregion borders length are significantly lower. However, the differences of segmentation index are higher. The average value for all microregions are 57, with 29 for lithogenic and 82 for hydrogenic regional units. The average height of microregion fluctuate from 58 m a.s.l. to 217 m a.s.l. (fig. 4). The slopes fluctuate from 1,3° (glacial channel region) to 7,5° (glacial upland region), but differences between types of microregions are low. The differences of TWI value are higher. The average TWI for all microregions is 10,8, with 8,7 for lithogenic and 12,7 for hydrogenic regional units. This difference empower to topographic wetness index application for microregions delimitation. The comparison of author's microregion delimitation for Cassubian Lakeland with studies of another geographers showed the presumable existence of more regional division levels than recommended by J. Kondracki (1994). T. Gacki and J. Szukalski (1979) proposed 20 submesoregions for study Lakeland and 31 microregions for central part of this area (about 7%). M. Przewoźniak (1985) proposed 65 microregions for 85% of Cassubian Lakeland and M. Kistowski propose 78 microregions in whole region. The conclusion is that this propositions concern two levels of physical-geographical regionalisation: microregions (submesoregions in terminology of Gacki and Szukalski) and nanoregions (formerly called microregions by most of authors ). The acceptable geographical scale for microregions delimitation is 1 :50.000 but nanoregions should be delimitated with accuracy correspond with local scale (1: 10.000). The further discussion of these problems and particular methodological solutions is recommended.