Wyniki wyszukiwania - Biblioteka Nauki

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Interannual Variation of the Growing Season Maximum Normalized Difference Vegetation Index, MNDVI, and Its Relationship with Climatic Factors on the Tibetan Plateau

100%

Wang S.-H. , Sun W. , Li S.-W. , Shen Z.-X. , Fu G.

Polish Journal of Ecology

|

2015

|

tom Vol. 63, nr 3

424--439

EN

The effects of the growing season climatic factors (i.e., temperature, precipitation, vapor pressure and relative humidity) on the growing season maximum normalized difference vegetation index (MNDVI), which can mirror the aboveground net primary production and the vegetation maximum absorbed ability of photosynthetically active radiation, were examined during the period from 2000 to 2012 on the Tibetan Plateau. The effects of climatic factors on the MNDVI changed with vegetation types, which was probably due to the fact that the changes of climatic factors differed with the type of vegetation. There was a significant increasing trend for the spatially averaged MNDVI of the vegetation area over the entire plateau. Approximately 16 and 3% of the vegetation area demonstrated a significant MNDVI increasing and decreasing trend, respectively. The MNDVI was significantly affected by relative humidity and vapor pressure, but not affected by temperature and precipitation over the entire plateau. Our findings suggested that the environmental humidity played a predominant role in affecting the variation of MNDVI over the entire Tibetan Plateau.

2

Interannual variation of the growing season maximum normalized difference vegetation index, MNDVI, and its relationship with climatic factors on the Tibetan Plateau

100%

Wang S.-H. , Sun W. , Li S.-W. , Shen Z.-X. , Fu G.

Polish Journal of Ecology

|

2015

|

tom 63

|

nr 3

EN

The effects of the growing season climatic factors (i.e., temperature, precipitation, vapor pressure and relative humidity) on the growing season maximum normalized difference vegetation index (MNDVI), which can mirror the aboveground net primary production and the vegetation maximum absorbed ability of photosynthetically active radiation, were examined during the period from 2000 to 2012 on the Tibetan Plateau. The effects of climatic factors on the MNDVI changed with vegetation types, which was probably due to the fact that the changes of climatic factors differed with the type of vegetation. There was a significant increasing trend for the spatially averaged MNDVI of the vegetation area over the entire plateau. Approximately 16 and 3% of the vegetation area demonstrated a significant MNDVI increasing and decreasing trend, respectively. The MNDVI was significantly affected by relative humidity and vapor pressure, but not affected by temperature and precipitation over the entire plateau. Our findings suggested that the environmental humidity played a predominant role in affecting the variation of MNDVI over the entire Tibetan Plateau.

3

The soil drying along the increase of warming masks the relation between temperature and soil respiration in an Alpine meadow of Northern Tibet

72%

Shen Z.-X. , Wang J.-W. , Sun W. , Li S.-W. , Fu G. , Zhang X.-Z. , Zhang Y.-J. , Yu C.-Q. , Shi P.-L. , He Y.-T.

Polish Journal of Ecology

|

2016

|

tom 64

|

nr 1

EN

A warming experiment with two magnitudes was performed in an alpine meadow of Northern Tibet since late June, 2013. Open top chambers (OTCs) with two top diameters (0.60 m and 1.00 m) were used to increase soil temperature. Soil respiration (Rs) was measured during the growing season in 2013–2014. The OTCs with top diameters of 1.00 m and 0.60 m increased soil temperature by 1.30 and 3.10oC, respectively, during the whole study period, but decreased soil moisture by 0.02 and 0.05 m³ m⁻³, respectively. However, the two patters of OTCs did not affect Rs. These results implied that a higher warming did not result in a higher Rs but a greater soil drying. Therefore, a higher warming may not cause a higher soil respiration, which was most likely due to the fact that a higher warming may result in a greater soil drying.

4

The Soil Drying Along the Increase of Warming Masks the Relation between Temperature and Soil Respiration in an Alpine Meadow of Northern Tibet

72%

Shen Z.-X. , Wang J.-W. , Sun W. , Li S.-W. , Fu G. , Zhang X.-Z. , Zhang Y.-J. , Yu C.-Q. , Shi P.-L. , He Y.-T.

Polish Journal of Ecology

|

2016

|

tom Vol. 64, nr 1

125--129

EN

A warming experiment with two magnitudes was performed in an alpine meadow of Northern Tibet since late June, 2013. Open top chambers (OTCs) with two top diameters (0.60 m and 1.00 m) were used to increase soil temperature. Soil respiration (Rs) was measured during the growing season in 2013–2014. The OTCs with top diameters of 1.00 m and 0.60 m increased soil temperature by 1.30 and 3.10oC, respectively, during the whole study period, but decreased soil moisture by 0.02 and 0.05 m3 m-3, respectively. However, the two patters of OTCs did not affect Rs . These results implied that a higher warming did not result in a higher Rs but a greater soil drying. Therefore, a higher warming may not cause a higher soil respiration, which was most likely due to the fact that a higher warming may result in a greater soil drying.