scholarly journals A 30 year monthly 5 km gridded surface elevation time series for the Greenland Ice Sheet from multiple satellite radar altimeters

2021 ◽  
Author(s):  
Baojun Zhang ◽  
Zemin Wang ◽  
Jiachun An ◽  
Tingting Liu ◽  
Hong Geng
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Time Series Data ◽  
Spatial Scales ◽  
European Space Agency ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Surface Elevation ◽  
Series Data ◽  
Satellite Radar

Abstract. A long-term time series of ice sheet surface elevation change (SEC) is important for study of ice sheet variation and its response to climate change. In this study, we used an updated plane-fitting least-squares regression strategy to generate a 30 year surface elevation time series for the Greenland Ice Sheet (GrIS) at monthly temporal resolution and 5 × 5 km grid spatial resolution using ERS‐1, ERS‐2, Envisat, and CryoSat‐2 satellite radar altimeter observations obtained between August 1991 and December 2020. The accuracy and reliability of the time series are effectively guaranteed by application of sophisticated corrections for intermission bias and interpolation based on empirical orthogonal function reconstruction. Validation using both airborne laser altimeter observations and the European Space Agency GrIS Climate Change Initiative (CCI) product indicated that our merged surface elevation time series is reliable. The accuracy and dispersion of errors of SECs of our results were 19.3 % and 8.9 % higher, respectively, than those of CCI SECs, and even 30.9 % and 19.0 % higher, respectively, in periods from 2006–2010 to 2010–2014. Further analysis showed that our merged time series could provide detailed insight into GrIS SEC on multiple temporal (up to 30 years) and spatial scales, thereby providing opportunity to explore potential associations between ice sheet change and climatic forcing. The merged surface elevation time series data are available at http://dx.doi.org/10.11888/Glacio.tpdc.271658 (Zhang et al., 2021).

Growth rings across the Tree of Life: demographic insights from biogenic time series data

2021 ◽  
pp. 77-96
Author(s):  
Margaret E. K. Evans ◽  
Bryan A. Black ◽  
Donald A. Falk ◽  
Courtney L. Giebink ◽  
Emily L. Schultz
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Spatial Scales ◽  
Ocean Dynamics ◽  
Individual Growth ◽  
Series Data ◽  
Rate Variation ◽  
Sampling Effort ◽  
Growth Rings ◽  
Demographic Processes

Biogenic time series data can be generated in a single sampling effort, offering an appealing alternative to the slow process of revisiting or recapturing individuals to measure demographic rates. Annual growth rings formed by trees and in the ear bones of fish (i.e. otoliths) are prime examples of such biogenic time series. They offer insight into not only the process of growth but also birth, death, movement, and evolution, sometimes at uniquely deep temporal and large spatial scales, well beyond 5–30 years of data collected in localised study areas. This chapter first reviews the fundamentals of how tree-ring and otolith time series data are developed and analysed (i.e. dendrochronology and sclerochronology), then surveys growth rings in other organisms, along with microstructural or microcompositional variation in growth rings, and other records of demographic processes. It highlights the answers to demographic questions revealed by these time series data, such as the influence of environmental (atmospheric or ocean) conditions, competition, and disturbances on demographic processes, and the genetic versus plastic basis of individual growth and traits that influence growth. Lastly, it considers how spatial networks of biogenic, annually resolved time series data can offer insights into the importance of macrosystem atmospheric and ocean dynamics on multispecies, trophic dynamics. The authors encourage demographers to integrate the complementary information contained in biogenic time series data into population models to better understand the drivers of vital rate variation and predict the impacts of global change.

scholarly journals Splendide Mendax: False Label Claims About High and Rising Alcohol Content of Wine

2015 ◽  
Vol 10 (3) ◽  
pp. 275-313 ◽  
Author(s):  
Julian M. Alston ◽  
Kate B. Fuller ◽  
James T. Lapsley ◽  
George Soleas ◽  
Kabir P. Tumber
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Time Series Data ◽  
Consumer Preferences ◽  
Series Data ◽  
Alcohol Content ◽  
Demand Shifts ◽  
Expert Ratings ◽  
Jel Classifications

AbstractAre wine alcohol labels accurate? If not, why? We explore the high and rising alcohol content of wine and examine incentives for false labeling, including the roles of climate, evolving consumer preferences, and expert ratings. We draw on international time-series data from a large number of countries that experienced different patterns of climate change and influences of policy and demand shifts. We find systematic patterns that suggest that rising wine alcohol content may be a nuisance by-product of producer responses to perceived market preferences for wines having more-intense flavours, possibly in conjunction with evolving climate. (JEL Classifications: D22, L15, L66, Q18, Q54).

scholarly journals Climate Change Driven Food Inflation in Ethiopia?

2018 ◽  
Vol 8 (1) ◽  
pp. 13-22
Author(s):  
Berhe Gebregewergs Hagos
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Time Series Data ◽  
Series Data ◽  
Average Price ◽  
Ceteris Paribus ◽  
Distributed Lag ◽  
Distributed Lag Model ◽  
Lag Model ◽  
Food Inflation

The research dealt with the relationships between temperature variability and price of food stuffs in Tigrai using 84 months collected time series data thereby applied a Univariate econometric tool and finite Distributed Lag Model in defining the variables and outcome of the study. As a result, the econometric regression analysis witnessed that a 1oC temperature rise contributed the average price of food stuffs such as barley price rose up by 80 percent, maize 186 percent, sorghum close to 275 percent, wheat 60 percent, and 170 percent in white Teff over the years, ceteris paribus.

scholarly journals Ice-Sheet Surface Elevation and Changes Observable by Satellite Radar Altimetry

1979 ◽  
Vol 24 (90) ◽  
pp. 491-493 ◽  
Author(s):  
H. Jay Zwally ◽  
R. L. Brooks ◽  
H. Ray Stanley ◽  
W. J. Campbell
Keyword(s):  
Drainage Basin ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
The State ◽  
Surface Elevation ◽  
Radar Altimeter ◽  
Major Question ◽  
The Status ◽  
Satellite Radar ◽  
Ice Sheet Dynamics

Abstract A major question in ice-sheet dynamics is the state of balance between the net mass input and ice flow. Since an imbalance produces a change in surface elevation, the state of balance can be studied by monitoring the elevation, and this has been accomplished by surface-leveling techniques in a few locations. Due to the requirement for accurate and repetitive measurements over large areas, it is not practical to determine the status of balance of an entire ice sheet or even a major drainage basin by conventional techniques. Now, recent results from satellite-borne radar altimeter measurements over the Greenland ice sheet demonstrate the feasibility of accurately measuring and monitoring the topography of large ice masses. The application of this new technique offers the possibility of making a meaningful mass-balance determination and for detecting actual or potential ice-sheet surges.

scholarly journals ESA's Ice Sheets CCI: validation and inter-comparison of surface elevation changes derived from laser and radar altimetry over Jakobshavn Isbræ, Greenland – Round Robin results

2013 ◽  
Vol 7 (6) ◽  
pp. 5433-5460
Author(s):  
J. F. Levinsen ◽  
K. Khvorostovsky ◽  
F. Ticconi ◽  
A. Shepherd ◽  
R. Forsberg ◽  
...  
Keyword(s):  
Drainage Basin ◽  
European Space Agency ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Round Robin ◽  
Surface Elevation ◽  
Optimal Method ◽  
Radar Altimetry ◽  
Elevation Changes

Abstract. In order to increase the understanding of the changing climate, the European Space Agency has launched the Climate Change Initiative (ESA CCI), a program which joins scientists and space agencies into 13 projects either affecting or affected by the concurrent changes. This work is part of the Ice Sheets CCI and four parameters are to be determined for the Greenland Ice Sheet (GrIS), each resulting in a dataset made available to the public: Surface Elevation Changes (SEC), surface velocities, grounding line locations, and calving front locations. All CCI projects have completed a so-called Round Robin exercise in which the scientific community was asked to provide their best estimate of the sought parameters as well as a feedback sheet describing their work. By inter-comparing and validating the results, obtained from research institutions world-wide, it is possible to develop the most optimal method for determining each parameter. This work describes the SEC Round Robin and the subsequent conclusions leading to the creation of a method for determining GrIS SEC values. The participants used either Envisat radar or ICESat laser altimetry over Jakobshavn Isbræ drainage basin, and the submissions led to inter-comparisons of radar vs. altimetry as well as cross-over vs. repeat-track analyses. Due to the high accuracy of the former and the high spatial resolution of the latter, a method, which combines the two techniques will provide the most accurate SEC estimates. The data supporting the final GrIS analysis stem from the radar altimeters on-board Envisat, ERS-1 and ERS-2. The accuracy of laser data exceeds that of radar altimetry; the Round Robin analysis has, however, proven the latter equally capable of dealing with surface topography thereby making such data applicable in SEC analyses extending all the way from the interior ice sheet to margin regions. This shows good potential for a~future inclusion of ESA CryoSat-2 and Sentinel-3 radar data in the analysis, and thus for obtaining reliable SEC estimates throughout the entire GrIS.

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