Freshwater availability is changing worldwide. Here we quantify 34 trends in terrestrial water storage observed by the Gravity Recovery and Climate Experiment (GRACE) satellites during 2002–2016 and categorize their drivers as natural interannual variability, unsustainable groundwater consumption, climate change or combinations thereof. Several of these trends had been lacking thorough investigation and attribution, including massive changes in northwestern China and the Okavango Delta. Others are consistent with climate model predictions. This observation-based assessment of how the world’s water landscape is responding to human impacts and climate variations provides a blueprint for evaluating and predicting emerging threats to water and food security.

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Emerging trends in global freshwater availability.

1995年Yoshida在分析一例慢性胰腺炎病例时指出，其符合自身免疫病的特点，首先提出自身免疫性胰腺炎（AIP）的概念。2003年Kamisawa等证明，AIP患者胰腺、胆道、肝门脉区、淋巴结等组织器官均有IgG+4浆细胞和CD+4、CD+8T细胞浸润，指出AIP不仅仅是胰腺炎，而是一种系统性疾病的胰腺损害，称之为IgG4相关的自身免疫病，或IgG4相关硬化性疾病，主要表现为自身免疫性胰腺炎、硬化性胆管炎、硬化性涎腺炎（包括Mikulicz′s病和Kuttner′s瘤）、腹膜后纤维化，伴淋巴结病，有些表现为炎性假瘤，病理为IgG+4浆细胞浸润、组织纤维化和硬化性改变，伴闭塞性静脉炎。近年来也有学者将此类疾病称之为IgG4阳性的多器官淋巴增殖综合征（IgG+4MOLPS），受累器官与干燥综合征相似，高IgG4γ球蛋白血症和多器官IgG+4浆细胞浸润是其特点，糖皮质激素（以下简称激素）治疗反应好。

. The International Centre for Global Earth Models (ICGEM,
 http://icgem.gfz-potsdam.de/ , last access: 6 May 2019) hosted at the
GFZ German Research Centre for Geosciences (GFZ) is one of the five services
coordinated by the International Gravity Field Service (IGFS) of the
International Association of Geodesy (IAG). The goal of the ICGEM service is
to provide the scientific community with a state-of-the-art archive of static
and temporal global gravity field models of the Earth, and develop and
operate interactive calculation and visualization services of gravity field
functionals on user-defined grids or at a list of particular points via its
website. ICGEM offers the largest collection of global gravity field models,
including those from the 1960s to the 1990s, as well as the most recent ones,
which have been developed using data from dedicated satellite gravity
missions, CHAMP, GRACE, GOCE, advanced processing methodologies, and
additional data sources such as satellite altimetry and terrestrial gravity.
The global gravity field models have been collected from different
institutions at international level and after a validation process made
publicly available in a standardized format with DOI numbers assigned through
GFZ Data Services. The development and maintenance of such a unique platform
is crucial for the scientific community in geodesy, geophysics, oceanography,
and climate research. In this article, we present the development history and
future plans of ICGEM and its current products and essential services. We
present the ICGEM's data by means of Earth's static, temporal, and
topographic gravity field models as well as the gravity field models of other
celestial bodies together with examples produced by the ICGEM's calculation
and 3-D visualization services and give an insight into how the ICGEM service
can additionally contribute to the needs of research and society.

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ICGEM – 15 years of successful collection and distribution of global gravitational models, associated services, and future plans

Glaciers outside of the ice sheets are known to be important contributors to sea level rise. In this work, we provide an overview of changes in the mass of the world's glaciers, excluding those in Greenland and Antarctica, between 2002 and 2016, based on satellite gravimetry observations of the Gravity Recovery and Climate Experiment (GRACE). Glaciers lost mass at a rate of 199 ± 32 Gt yr −1 during this 14-yr period, equivalent to a cumulative sea level contribution of 8 mm. We present annual mass balances for 17 glacier regions, that show a qualitatively good agreement with published estimates from in situ observations. We find that annual mass balance varies considerably from year to year, which can in part be attributed to changes in the large-scale circulation of the atmosphere. These variations, combined with the relatively short observational record, hamper the detection of acceleration of glacier mass loss. Our study highlights the need for continued observations of the Earth's glacierized regions.

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Global glacier mass loss during the GRACE satellite mission (2002-2016)

The primary objective of the gravity recovery and climate experiment followon (GRACE-FO) satellite mission, due for launch in August 2017, is to continue the GRACE time series of global monthly gravity field models. For this, evolved versions of the GRACE microwave instrument, GPS receiver, and accelerometer will be used. A secondary objective is to demonstrate the effectiveness of a laser ranging interferometer (LRI) in improving the satellite-to-satellite tracking measurement performance. In order to investigate the expected enhancement for Earth science applications, we have performed a full-scale simulation over the nominal mission lifetime of 5 years using a realistic orbit scenario and error assumptions both for instrument and background model errors. Unfiltered differences between the synthetic input and the finally recovered time-variable monthly gravity models show notable improvements with the LRI, on a global scale, of the order of 23 %. The gain is realized for wavelengths smaller than 240 km in case of Gaussian filtering but decreases to just a few percent when anisotropic filtering is applied. This is also confirmed for some typical regional Earth science applications which show randomly distributed patterns of small improvements but also degradations when using DDK4-filtered LRI-based models. Analysis of applied error models indicates that accelerometer noise followed by ocean tide and non-tidal mass variation errors are the main contributors to the overall GRACE-FO gravity model error. Improvements in these fields are therefore necessary, besides optimized constellations, to make use of the increased LRI accuracy and to significantly improve gravity field models from next-generation gravity missions.

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What Can be Expected from the GRACE-FO Laser Ranging Interferometer for Earth Science Applications?

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2019JB017415

Beate Klinger

Papers

ITSG-Grace2018: Overview and Evaluation of a New GRACE-Only Gravity Field Time Series

The role of accelerometer data calibration within GRACE gravity field recovery: Results from ITSG-Grace2016

ITSG-Grace2014: a new GRACE gravity field release computed in Graz

ITSG-Grace2018: Monthly, Daily and Static Gravity Field Solutions from GRACE

ITSG-Grace2016 - Monthly and Daily Gravity Field Solutions from GRACE