Rasim DENİZ, Hasan YILDIZ

Mareograf ve sabit GPS ile uzun dönemli mutlak deniz seviyesi değişimleri

Norveç kıyılarındaki ANDENES ve TREGDE mareograf istasyonlarındaki uzun dönemli mutlak deniz seviyesi değişimleri mareograf ve Sabit GPS zaman serilerinin analizi ile araştırılmıştır. Aylık ortalama deniz seviyesi ile Sabit GPS yükseklik zaman serilerindeki periyodik sinyallerin konumsal ve zamansal karakteri Deneysel Ortogonal Fonksiyon ve spektral analiz yöntemleri kullanılarak belirlenmiştir. Hem mareograf hem de Sabit GPS yükseklik zaman serisi doğrusal trendleri En Küçük Karelerle harmonik analiz yöntemiyle hesaplanmıştır. TREGDE’de anlamlı bir deniz seviyesi trendi bulunmazken, ANDENES mareograf istasyonunda uzun dönemli mutlak deniz seviyesinin 2.44 ± 0.21 mm/yıl hızla yükseldiği belirlenmiştir. Bu değer literatürdeki 1-3 mm/yıl düzeyindeki global deniz seviyesi değişimleri ile uyumludur.

Long term absolute sea level changes by tide gauge and continuous GPS data

Long term absolute sea level changes at ANDENES and TREGDE tide gauges at Norwegian coasts are investigated by the analysis of the tide gauge and Continuous GPS time series. The spatial and temporal character of interannual to interdecadal sea level varitaions in tide gauge monthly mean sea level data and periodic signals in Continuous GPS height time series are determined by using Emprical Ortogonal Function and spectral analysis methods. The linear trends of both tide gauge and Continuous GPS height time series are calculated by harmonic analysis method with Least Squares Estimation. While no significant relative sea level trend is found at TREGDE, 2.04 ± 0.19 mm/year is found at ANDENES. While no significant absolute vertical movement is determined at TGDE and ANDE, the absolute vertical velocity of ANDO Continuous GPS station is 0.40 ± 0.10 mm/year and generally agrees with 0.89 mm/year land uplift determined by a Post Glacial Rebound model. The absolute sea level at ANDENES tide gauge is determined to be rising with a rate of 2.44 ± 0.21 mm/year by combining the vertical velocity of ANDE Continuous GPS station with the relative sea level trend. This value is consistent with the global sea level rise estimates which is in the order of 1-3 mm/year.

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