Real-time soft error testing system for large-area QDR II+ SRAM array on the Tibetan Plateau

The timing of lake-level fluctuations on the Tibetan Plateau and their relationship with climatic changes is still under debate, and the main reason for this is the lack of suitable archives for reconstructing the paleohydrology and paleoclimatology of the lakes. Here, we present the results of analyses of the shell geochemistry of Radix sp. from an exposed terrace of Nam Co lake on the south-central Tibetan Plateau. Optically stimulated luminescence (OSL) dating reveals that deep-water lacustrine sediments formed between ca. 4.4 and 2.2 ka, suggesting a high and stable lake level significantly above the present. The results of Sr/Ca, δ13C and δ18O analyses of the fossil shells of Radix sp. indicate that during the mid- to late-Holocene, lake-level variations in Nam Co were mainly controlled by variations in the Indian Summer Monsoon. A trend of decreasing evaporation also played an important role. Comparison with other results suggests a consistent pattern of mid- to late-Holocene lake-level changes across a large area of the Tibetan Plateau and adjacent regions to the south, which had a similar causal mechanism. Finally, our results indicate that fossil shells of the gastropod Radix sp. of the lakes on the Tibetan Plateau are a valuable archive for reconstructing the regional paleohydrology and paleoclimatology.

Download Full-text

Contribution of the Autumn Tibetan Plateau Snow Cover to Seasonal Prediction of North American Winter Temperature

Journal of Climate ◽

10.1175/2010jcli3889.1 ◽

2011 ◽

Vol 24 (11) ◽

pp. 2801-2813 ◽

Cited By ~ 78

Author(s):

Hai Lin ◽

Zhiwei Wu

Keyword(s):

Tibetan Plateau ◽

Snow Cover ◽

Real Time ◽

Empirical Model ◽

North American ◽

Geopotential Height ◽

Seasonal Prediction ◽

Height Anomaly ◽

The Tibetan Plateau ◽

Geopotential Height Anomaly

Abstract Predicting surface air temperature (T) is a major task of North American (NA) winter seasonal prediction. It has been recognized that variations of the NA winter T’s can be associated with El Niño–Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). This study presents observed evidence that variability in snow cover over the Tibetan Plateau (TP) and its adjacent areas in prior autumn (September–November) is significantly correlated with the first principal component (PC1) of the NA winter T’s, which features a meridional seesaw pattern over the NA continent. The autumn TP snow cover anomaly can persist into the following winter through a positive feedback between snow cover and the atmosphere. A positive TP snow cover anomaly may induce a negative sea level pressure and geopotential height anomaly over the eastern North Pacific, a positive geopotential height anomaly over Canada, and a negative anomaly over the southeastern United States—a structure very similar to the positive phase of the Pacific–North America (PNA) pattern. This pattern usually favors the occurrence of a warm–north, cold–south winter over the NA continent. When a negative snow cover anomaly occurs, the situation tends to be opposite. Since the autumn TP snow cover shows a weak correlation with ENSO, it provides a new predictability source for NA winter T’s. Based on the above results, an empirical model is constructed to predict PC1 using a combination of autumn TP snow cover and other sea surface temperature anomalies related to ENSO and the NAO. Hindcasts and real forecasts are performed for the 1972–2003 and 2004–09 periods, respectively. Both show a promising prediction skill. As far as PC1 is concerned, the empirical model hindcast performs better than the ensemble mean of four dynamical models from the Canadian Meteorological Centre. Particularly, the real forecast of the empirical model exhibits a better performance in predicting the extreme phases of PC1—that is, the extremely warm winter over Canada in 2009/10—should the model include the autumn TP snow cover impacts. Since all these predictors can be readily monitored in real time, this empirical model provides a real-time forecast tool for NA winter climate.

Download Full-text

Exposure dating of the giant fossil landslide in the upper reaches of the Yellow River, China

10.5194/egusphere-egu2020-21622 ◽

2020 ◽

Author(s):

Danhui Li ◽

Shibiao Bai

Keyword(s):

Tibetan Plateau ◽

Yellow River ◽

Cosmic Ray ◽

Luminescence Dating ◽

The Yellow River ◽

The Tibetan Plateau ◽

Large Area ◽

Ancient Landslide ◽

Exposure Dating ◽

Alternative Means

Abstract:&#160;The upper reaches of the Yellow River&#160;is located in&#160;the transition zone between the Tibetan Plateau and the Loess&#160;Plateau, of which a large area is covered by extensive loess&#160;deposits. The Tibetan Plateau uplift has resulted in a high&#160;geomorphic activity.&#160;One landslide inventory of this region is compiled, which includes about 100 giant ancient landslides. Furthermore, their positions,&#160;boundaries, area, volume and so on&#160;are managed in geographic information system&#160;(GIS).&#160;The determinations of those giant ancient ages are an important&#160;step towards understanding the causes, frequency, hazards, the earth surface uplift and landscape-lowering rate.&#160;Development of OSL techniques has provided another alternative means of dating landslide and colluvial sediment. There are many challenges&#160;and some problems&#160;of luminescence dating of landslide&#160;and colluvial deposits&#160;because of the insufficiently bleached sediments&#160;condition. There are also some controversial issues existing in present studies of landslide dating by using&#160;Cosmic Ray Exposure (CRE) method.&#160;The study use the landslide pond sediments&#160;and the dammed lake deposits&#160;to dating the giant ancient landslide&#160;using OSL techniques,&#160;the surface of landslide scarp&#160;and boulders&#160;to dating the giant ancient landslide&#160;using CRE.&#160;The two dating&#160;results based on different datable&#160;landslide elements&#160;were&#160;be cross-validated&#160;using the typical giant ancient landslides in the upper reaches of the Yellow River, China.Keywords: Giant fossil landslide; cosmogenic&#160;nuclides chronology; luminescence dating, the upper reaches of the Yellow River&#160;

Download Full-text

A New and Simplified Approach for Estimating the Daily River Discharge of the Tibetan Plateau Using Satellite Precipitation: An Initial Study on the Upper Brahmaputra River

Remote Sensing ◽

10.3390/rs12132103 ◽

2020 ◽

Vol 12 (13) ◽

pp. 2103

Author(s):

Tian Zeng ◽

Lei Wang ◽

Xiuping Li ◽

Lei Song ◽

Xiaotao Zhang ◽

...

Keyword(s):

Time Series ◽

Tibetan Plateau ◽

Real Time ◽

River Discharge ◽

The Tibetan Plateau ◽

Time Lags ◽

Precipitation Data ◽

Precipitation Time Series ◽

Discharge Data ◽

Satellite Precipitation

Collecting in situ observations from remote, high mountain rivers presents major challenges, yet real-time, high temporal resolution (e.g., daily) discharge data are critical for flood hazard mitigation and river management. In this study, we propose a method for estimating daily river discharge (RD) based on free, operational remote sensing precipitation data (Tropical Rainfall Measuring Mission (TRMM), since 2001). In this method, an exponential filter was implemented to produce a new precipitation time series from daily basin-averaged precipitation data to model the time lag of precipitation in supplying RD, and a linear-regression relationship was constructed between the filtered precipitation time series and observed discharge records. Because of different time lags in the wet season (rainfall-dominant) and dry season (snowfall-dominant), the precipitation data were processed in a segmented way (from June to October and from November to May). The method was evaluated at two hydrological gauging stations in the Upper Brahmaputra (UB) river basin, where Nash–Sutcliffe Efficiency (NSE) coefficients for Nuxia (>0.85) and Yangcun (>0.80) indicate good performance. By using the degree-day method to estimate the snowmelt and acquire the time series of new active precipitation (rainfall plus snowmelt) in the target basins, the discharge estimations were improved (NSE > 0.9 for Nuxia) compared to the original data. This makes the method applicable for most rivers on the Tibetan Plateau, which are fed mainly by precipitation (including snowfall) and are subject to limited human interference. The method also performs well for reanalysis precipitation data (Chinese Meteorological Forcing Dataset (CMFD), 1980–2000). The real-time or historical discharges can be derived from satellite precipitation data (or reanalysis data for earlier historical years) by using our method.

Download Full-text