Spatially and temporally resolved ice loss in High Mountain Asia and the Gulf of Alaska observed by CryoSat-2 swath altimetry between 2010 and 2019

International audienceGlaciers are currently the largest contributor to sea level rise after ocean thermal expansion, contributing ∼ 30 % to the sea level budget. Global monitoring of these regions remains a challenging task since global estimates rely on a variety of observations and models to achieve the required spatial and temporal coverage, and significant differences remain between current estimates. Here we report the first application of a novel approach to retrieve spatially resolved elevation and mass change from radar altimetry over entire mountain glaciers areas. We apply interferometric swath altimetry to CryoSat-2 data acquired between 2010 and 2019 over High Mountain Asia (HMA) and in the Gulf of Alaska (GoA). In addition, we exploit CryoSat's monthly temporal repeat to reveal seasonal and multiannual variation in rates of glaciers' thinning at unprecedented spatial detail. We find that during this period, HMA and GoA have lost an average of −28.0 ± 3.0 Gt yr−1 (−0.29 ± 0.03 m w.e. yr−1) and −76.3 ± 5.7 Gt yr−1 (−0.89 ± 0.07 m w.e. yr−1), respectively, corresponding to a contribution to sea level rise of 0.078 ± 0.008 mm yr−1 (0.051 ± 0.006 mm yr−1 from exorheic basins) and 0.211 ± 0.016 mm yr−1. The cumulative loss during the 9-year period is equivalent to 4.2 % and 4.3 % of the ice volume, respectively, for HMA and GoA. Glacier thinning is ubiquitous except for in the Karakoram-Kunlun region, which experiences stable or slightly positive mass balance. In the GoA region, the intensity of thinning varies spatially and temporally, with acceleration of mass loss from −0.06 ± 0.33 to −1.1 ± 0.06 m yr−1 from 2013, which correlates with the strength of the Pacific Decadal Oscillation. In HMA ice loss is sustained until 2015-2016, with a slight decrease in mass loss from 2016, with some evidence of mass gain locally from 2016-2017 onwards

Ice loss in High Mountain Asia and the Gulf of Alaska observed by CryoSat-2 swath altimetry between 2010 and 2019

We report the first application of a novel approach to retrieve spatially-resolved elevation change from radar altimetry over entire mountain glaciers areas. We apply interferometric swath altimetry to CryoSat-2 data acquired between July 2010 and July 2019 over High Mountain Asia (HMA) and in the Gulf of Alaska (GoA). We bin swath elevation data into 100 x 100 km bins, remove the topography with a reference DEM and generate linear rates of elevation changes for each bin individually using a weighted regression model. We exclude solutions that that did not fulfil a set of quality criteria based on elevation change uncertainties, temporal completeness, interannual changes and stability of regression results. To extrapolate missing data, hypsometric averaging is applied. We find that during the study period, HMA and GoA have lost an average of –28.0 ± 3.0 Gt yr–1 (–0.29 ± 0.03 m w.e. yr–1) and –76.3 ± 5.7 Gt yr–1 (–0.89 ± 0.07 m w.e. yr–1) respectively. Glacier thinning is ubiquitous except for the Karakoram-Kunlun region experiencing stable or slightly positive mass balanc

Time-resolved gas thermometry by laser-induced grating spectroscopy with a high-repetition rate laser system

Thermometry using Laser Induced Grating Spectroscopy (LIGS) is reported using a high– repetition rate laser system, extending the technique to allow time–resolved measurements of gas dynamics. LIGS signals were generated using the second harmonic output at 532 nm of a commercially available high– repetition rate Nd:YAG laser with nitrogen dioxide as molecular seed. Measurements at rates up to 10 kHz were demonstrated under static cell conditions. Transient temperature changes of the same gas contained in a cell subjected to rapid compression by injection of gas were recorded at 1 kHz to derive the temperature evolution of the compressed gas showing temperature changes of 50 K on a time scale of 0.1 s with a measurement precision of 1.4 %. The data showed good agreement with an analytical thermodynamic model of the compression process

From abundance to scarcity: implications for the American tradition

(print) 108 p. ; 21 cmBoulding, K. E. The limits to progress in evolutionary systems.--Kammen, M. From scarcity to abundance--to scarcity?--Lipset, S. M. Growth, affluence, and the limits of futurolog

Using deep learning to model elevation differences between 2 radar and laser altimetry

peer reviewedSatellite and airborne observations of surface elevation are critical in understanding climatic and glaciological processes and quantifying their impact on changes in ice masses and sea level contribution. With the growing number of dedicated airborne campaigns and experimental and operational satellite missions, the science community has access to unprecedented and ever-increasing data. Combining elevation datasets allows potentially greater spatial-temporal coverage and improved accuracy; however, combining data from different sensor types and acquisition modes is difficult by differences in intrinsic sensor properties and processing methods. This study focuses on the combination of elevation measurements derived from ICESat-2 and Operation IceBridge LIDAR instruments and from CryoSat-2’s novel interferometric radar altimeter over Greenland. We develop a deep neural network based on sub-waveform information from CryoSat-2, elevation differences between radar and LIDAR, and additional inputs representing local geophysical information. A time series of maps are created showing observed LIDAR-radar differences and neural network model predictions. Mean LIDAR vs. interferometric radar adjustments and the broad spatial and temporal trends thereof are recreated by the neural network. The neural network also predicts radar-LIDAR differences with respect to waveform parameters better than a simple linear model; however, point level adjustments and the magnitudes of the spatial and temporal trends are underestimated

The Retinitis Pigmentosa Mutation c.3444+1G>A in CNGB1 Results in Skipping of Exon 32

Retinitis pigmentosa (RP) is a severe hereditary eye disorder characterized by progressive degeneration of photoreceptors and subsequent loss of vision. Two of the RP associated mutations were found in the CNGB1 gene that encodes the B subunit of the rod cyclic nucleotide-gated channel (CNGB1a). One of them (c.3444+1G>A) is located at the donor site of exon 32 and has been proposed to result in a frameshift and truncation of the last 28 aa of the corresponding protein. However, this ambiguous conclusion was not verified by experimental data. Recently, another study reported that the last 28 aa of CNGB1a harbor a motif required for the proper targeting of this subunit to rod photoreceptor outer segments. This suggests that defective targeting is the major cause for the RP phenotype in affected patients. Here, we investigated the splicing of c.3444+1G>A by exon trapping experiments and could demonstrate that instead of the proposed truncation of the last 28 aa this mutation leads to replacement of the last 170 aa of CNGB1a by 68 unrelated amino acids. The 170 aa deletion covers the complete distal C-terminus including the last 10 aa of an important alpha (αC) helix within the ligand-binding domain of CNGB1a. When expressed in a heterologous expression system the corresponding mutant full-length CNGB1a subunit was more susceptible to proteosomal degradation compared to the wild-type counterpart. In conclusion, our experimental data do not support the hypothesis proposed by the original study on the c.3444+1G>A mutation. Based on this, we suggest that apart from the defective targeting other mechanisms may be responsible for the RP phenotype in affected individuals

Temperature measurements under diesel engine conditions using laser induced grating spectroscopy

Crank angle-resolved temperatures have been measured using laser induced grating spectroscopy (LIGS) in a reciprocating rapid compression machine (RCM) to simulate diesel engine operating conditions. A portable LIGS system based on a pulsed Nd:YAG laser, fundamental emission at 1064 nm and the fourth harmonic at 266 nm, was used with a c.w. diode-pumped solid state laser as probe at 660 nm. Laser induced thermal grating scattering (LITGS) using resonant absorption by 1-methylnaphthalene, as a substitute fuel, of the 266 nm pump-radiation was used for temperature measurements during non-combusting cycles. Laser induced electrostrictive grating scattering (LIEGS) using 1064 nm pump-radiation was used to measure temperatures in both combusting and non-combusting cycles with good agreement with the results of LITGS measurements which had a single-shot precision of ± 15 K and standard error of ± 1.5 K. The accuracy was estimated to be ± 3 K based on the uncertainty involved in the modified equation of state used in the derivation from the LIGS measurements of sound speed in the gas. Differences in the in-cylinder bulk gas temperature between combusting and non-combusting cycles were unambiguously resolved and temperatures of 2300 ± 100 K, typical of flames, were recorded in individual cycles. The results confirm the potential for LIGS-based thermometry for high-precision thermometry of combustion under compression-ignition conditions

Cognitive representations of disability behaviours in people with mobility limitations : consistency with theoretical constructs

Disability is conceptualised as behaviour by psychological theory and as a result of bodily impairment by medical models. However, how people with disabilities conceptualise those disabilities is unclear. The purpose of this study was to examine disability representations in people with mobility disabilities. Thirteen people with mobility disabilities completed personal repertory grids (using the method of triads) applied to activities used to measure disabilities. Ten judges with expertise in health psychology then examined the correspondence between the elicited disability constructs and psychological and medical models of disability. Participants with mobility disabilities generated 73 personal constructs ofdisability. These constructs were judged consistent with the content of two psychological models, namely the theory of planned behaviour and social cognitive theory and with the main medical model of disability, the International Classification of Functioning Disability and Health.Individuals with activity limitations conceptualise activities in a manner that is compatible with both psychological and medical models. This ensures adequate communication in contexts where the medical model is relevant, e.g. clinical contexts, as well as in everyday conversation about activities and behaviours. Finally, integrated models of disability may be of value for theory driven interdisciplinary approaches to disability and rehabilitation

Integrated Epigenetics of Human Breast Cancer: Synoptic Investigation of Targeted Genes, MicroRNAs and Proteins upon Demethylation Treatment

The contribution of aberrant DNA methylation in silencing of tumor suppressor genes (TSGs) and microRNAs has been investigated. Since these epigenetic alterations are reversible, it became of interest to determine the effects of the 5-aza-2'-deoxycytidine (DAC) demethylation therapy in breast cancer at different molecular levels

Structure and evolutionary origin of Ca2+-dependent herring type II antifreeze protein

10.1371/journal.pone.0000548PLoS ONE26