|
Research Article: Long-term temporal variability of chlorophyll-a and sea surface temperature in the southern Caspian Sea using MODIS satellite observations (2002–2020)
|
| |
|
|
|
چکیده: (12 مشاهده) |
Sea surface temperature (SST) and chlorophyll-a (Chl-a) are important indicators of climatic variability and phytoplankton biomass. This study investigated temporal trends in SST and Chl-a and their relationship in the southern Caspian Sea at monthly and seasonal scales during 2002–2020. MODIS-Aqua and MODIS-Terra satellite data were used to construct long-term time series following standard image preprocessing, atmospheric correction, and retrieval using Multi‑Channel SST (MCSST) for SST and OC3M for Chl-a. Seasonal trends were assessed using the Mann–Kendall test, while the Pettitt’s test was applied to identify abrupt changes. Linear regression was used to examine the relationship between SST and Chl-a. Chl-a showed a significant increasing trend, with mean concentrations rising from 2.95 mg m⁻³ in 2002 to 4.52 mg m⁻³ in 2020. In contrast, mean SST increased slightly from 15.1°C to 16.1°C, but no significant monotonic trend was detected. The Pettitt’s test identified a significant change point in Chl-a around mid-2006. Regression analysis indicated a moderate positive relationship between SST and Chl-a, with SST explaining 57.5% of the observed variability (R²=0.575, p<0.05). The increasing Chl-a trend despite the absence of a significant SST trend suggests that factors beyond temperature, including nutrient inputs and river discharge, may contribute to phytoplankton variability. Overall, the findings highlight the value of long-term satellite observations for monitoring ecological changes in the southern Caspian Sea ecosystem.
|
|
| |
|
|
متن کامل [PDF 655 kb]
(3 دریافت)
|
|
نوع مطالعه: پژوهشي |
موضوع مقاله:
Ecology
|
|
|
|
|
|
|
| ارسال نظر درباره این مقاله |
|
|
|
