Climatic Controls on Spring Onset of the Tibetan Plateau Grasslands from 1982 to 2008

Zhang, Wenjiang; Yi, Yujun; Kimball, J. S.; Kim, Youngwook; Song, Kechao

doi:10.3390/rs71215847

Cited by 33 publications

(17 citation statements)

References 53 publications

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“…However, the considerable difference in the timing of earliest greening in 2013 and 2014 (beginning of May) versus 2015 (beginning of June), in combination with the clear decline in temperature sensitivity in 2015, indicated that day length was not the main driver of the SOS in these subarctic grasslands. Precipitation can play a role in SOS of subarctic and alpine grasslands, although its effect is not consistent, varying between nonexistent (Piao et al., ), positive (Fu, Piao, et al., ), negative (Chen et al., ; Sha, Zhong, Bai, Tan, & Li, ), and dependent on the specific situation (Shen, Piao, Cong, Zhang, & Janssens, ; Shen, Tang, Chen, Zhu, & Zheng, ; Zhang, Yi, Kimball, Kim, & Song, ). In this study, no major variation in soil water status occurred along the temperature gradients (Sigurdsson et al., ), especially in early spring, so it is unlikely that precipitation was an important determinant of the decelerating advance of SOS.…”

Section: Discussionmentioning

confidence: 99%

Phenological responses of Icelandic subarctic grasslands to short‐term and long‐term natural soil warming

Leblans

Sigurðsson

Vicca

et al. 2017

Global Change Biology

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The phenology of vegetation, particularly the length of the growing season (LOS; i.e., the period from greenup to senescence), is highly sensitive to climate change, which could imply potent feedbacks to the climate system, for example, by altering the ecosystem carbon (C) balance. In recent decades, the largest extensions of LOS have been reported at high northern latitudes, but further warming-induced LOS extensions may be constrained by too short photoperiod or unfulfilled chilling requirements. Here, we studied subarctic grasslands, which cover a vast area and contain large C stocks, but for which LOS changes under further warming are highly uncertain. We measured LOS extensions of Icelandic subarctic grasslands along natural geothermal soil warming gradients of different age (short term, where the measurements started after 5 years of warming and long term, i.e., warmed since ≥50 years) using ground-level measurements of normalized difference vegetation index. We found that LOS linearly extended with on average 2.1 days per °C soil warming up to the highest soil warming levels (ca. +10°C) and that LOS had the potential to extend at least 1 month. This indicates that the warming impact on LOS in these subarctic grasslands will likely not saturate in the near future. A similar response to short- and long-term warming indicated a strong physiological control of the phenological response of the subarctic grasslands to warming and suggested that genetic adaptations and community changes were likely of minor importance. We conclude that the warming-driven extension of the LOSs of these subarctic grasslands did not saturate up to +10°C warming, and hence that growing seasons of high-latitude grasslands are likely to continue lengthening with future warming (unless genetic adaptations or species shifts do occur). This persistence of the warming-induced extension of LOS has important implications for the C-sink potential of subarctic grasslands under climate change.

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Section: Discussionmentioning

confidence: 99%

Phenological responses of Icelandic subarctic grasslands to short‐term and long‐term natural soil warming

Leblans

Sigurðsson

Vicca

et al. 2017

Global Change Biology

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“…The delayed trend may be the product of increasingly severe aridity, unmet chilling or photoperiod requirements for plants [57], and a cooling trend in spring air temperatures [23]. Some studies have reported that SOS has continuously occurred earlier in the Tibetan Plateau [58]; the discrepancies among results may be the product of differences in vegetation index responses to vegetation growth between sensors [59] and/or measurements for estimating phenology. Furthermore, SOS trends in the Tibetan Plateau may vary with longitude [16] and elevation [23] due to variation in vegetation types and climate conditions; thus, the considerable spatial heterogeneity of the Tibetan Plateau may offset the positive and negative change trends observed among pixels [13], and the trend may not be significant or even distinguishable over the entire study area.…”

Section: Temporal Changes In Phenology At the Regional Scalementioning

confidence: 99%

Spatiotemporal Variability of Land Surface Phenology in China from 2001–2014

Luo

2017

Remote Sensing

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Abstract:Land surface phenology is a highly sensitive and simple indicator of vegetation dynamics and climate change. However, few studies on spatiotemporal distribution patterns and trends in land surface phenology across different climate and vegetation types in China have been conducted since 2000, a period during which China has experienced remarkably strong El Niño events. In addition, even fewer studies have focused on changes of the end of season (EOS) and length of season (LOS) despite their importance. In this study, we used four methods to reconstruct Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) dataset and chose the best smoothing result to estimate land surface phenology. Then, the phenophase trends were analyzed via the Mann-Kendall method. We aimed to assess whether trends in land surface phenology have continued since 2000 in China at both national and regional levels. We also sought to determine whether trends in land surface phenology in subtropical or high altitude areas are the same as those observed in high latitude areas and whether those trends are uniform among different vegetation types. The result indicated that the start of season (SOS) was progressively delayed with increasing latitude and altitude. In contrast, EOS exhibited an opposite trend in its spatial distribution, and LOS showed clear spatial patterns over this region that decreased from south to north and from east to west at a national scale. The trend of SOS was advanced at a national level, while the trend in Southern China and the Tibetan Plateau was opposite to that in Northern China. The transaction zone of the SOS within Northern China and Southern China occurred approximately between 31.4 • N and 35.2 • N. The trend in EOS and LOS were delayed and extended, respectively, at both national and regional levels except that of LOS in the Tibetan Plateau, which was shortened by delayed SOS onset more than by delayed EOS onset. The absolute magnitude of SOS was decreased after 2000 compared with previous studies, and the phenophase trends are species specific.

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“…The GIMMS3g NDVI record has an 8-km spatial resolution and a 15-day temporal interval, and was assembled from different NOAA Advanced Very High Resolution Radiometer (AVHRR) records accounting for various deleterious effects including calibration loss, orbital drift and volcanic eruptions [37]. The dynamic threshold method, which defined the threshold of vegetation growing-season onset and offset as 25% of the seasonal NDVI amplitude based on the multi-year average [2,38], was used to derive growing season onset, offset and duration [2,14,38]. Prior to the phenology analysis, the NDVI time series were filtered using the double logistic method from the Timesat Tool to remove outliers and fill data gaps [38].…”

Section: Remote Sensing Measurementsmentioning

confidence: 99%

Hydrological Response of Alpine Wetlands to Climate Warming in the Eastern Tibetan Plateau

Zhang

Song

et al. 2016

Remote Sensing

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Alpine wetlands in the Tibetan Plateau (TP) play a crucial role in the regional hydrological cycle due to their strong influence on surface ecohydrological processes; therefore, understanding how TP wetlands respond to climate change is essential for projecting their future condition and potential vulnerability. We investigated the hydrological responses of a large TP wetland complex to recent climate change, by combining multiple satellite observations and in-situ hydro-meteorological records. We found different responses of runoff production to regional warming trends among three basins with similar climate, topography and vegetation cover but different wetland proportions. The basin with larger wetland proportion (40.1%) had a lower mean runoff coefficient (0.173˘0.006), and also showed increasingly lower runoff level (´3.9% year´1, p = 0.002) than the two adjacent basins. The satellite-based observations showed an increasing trend of annual non-frozen period, especially in the wetland-dominated region (2.64 day¨year´1, p < 0.10), and a strong extension of vegetation growing-season (0.26-0.41 day¨year´1, p < 0.10). Relatively strong increasing trends in evapotranspiration (ET) (~1.00 mm¨year´1, p < 0.01) and the vertical temperature gradient above ground surface (0.043˝C¨year´1, p < 0.05) in wetland-dominant areas were documented from satellite-based ET observations and weather station records. These results indicate recent surface drying and runoff reduction of alpine wetlands, and their potential vulnerability to degradation with continued climate warming.

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Climatic Controls on Spring Onset of the Tibetan Plateau Grasslands from 1982 to 2008

Cited by 33 publications

References 53 publications

Phenological responses of Icelandic subarctic grasslands to short‐term and long‐term natural soil warming

Phenological responses of Icelandic subarctic grasslands to short‐term and long‐term natural soil warming

Spatiotemporal Variability of Land Surface Phenology in China from 2001–2014

Hydrological Response of Alpine Wetlands to Climate Warming in the Eastern Tibetan Plateau

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