Rapid adjustments are responses to forcing agents that cause a perturbation to the top of atmosphere energy budget but are uncoupled to changes in surface warming. Different mechanisms are ...responsible for these adjustments for a variety of climate drivers. These remain to be quantified in detail. It is shown that rapid adjustments reduce the effective radiative forcing (ERF) of black carbon by half of the instantaneous forcing, but for CO2 forcing, rapid adjustments increase ERF. Competing tropospheric adjustments for CO2 forcing are individually significant but sum to zero, such that the ERF equals the stratospherically adjusted radiative forcing, but this is not true for other forcing agents. Additional experiments of increase in the solar constant and increase in CH4 are used to show that a key factor of the rapid adjustment for an individual climate driver is changes in temperature in the upper troposphere and lower stratosphere.
Plain Language Summary
Long‐term global warming can be estimated with knowledge of how climate forcing agents affect the Earth's top‐of‐atmosphere energy imbalance or effective radiative forcing. Changes in climate forcers, such as greenhouse gases, the Sun's intensity, or emission of aerosol particles, typically impose a direct change in the energy budget, termed an instantaneous radiative forcing. Further to this, a climate forcer may induce changes in the atmosphere, such as a change in thermal structure, clouds, or humidity. These changes themselves, termed rapid adjustments, contribute to the top‐of‐atmosphere energy budget. Together, the instantaneous radiative forcing plus rapid adjustments equals the effective radiative forcing. We show that for different climate forcing agents, the rapid adjustments behave very differently and are driven by different atmospheric mechanisms. For example, rapid adjustments add to the instantaneous forcing for a carbon dioxide increase, due to a cooling of the stratosphere, but oppose instantaneous forcing for black carbon, driven by a warming troposphere and lowering of cloud height. Understanding rapid adjustments gives a more complete picture of the climate effects of different climate forcers.
Key Points
Rapid adjustments affect the Earth's energy balance in different ways for greenhouse gas, aerosol, and solar forcing
Radiative kernels and partial radiative perturbations are used to diagnose rapid adjustments from atmospheric and cloud changes
Noncloud adjustments agree well between models, whereas cloud adjustments exhibit more spread
The Generic Mapping Tools Version 6 Wessel, P.; Luis, J. F.; Uieda, L. ...
Geochemistry, geophysics, geosystems : G3,
November 2019, 2019-11-00, 20191101, Letnik:
20, Številka:
11
Journal Article
Recenzirano
Odprti dostop
The Generic Mapping Tools (GMT) software is ubiquitous in the Earth and ocean sciences. As a cross‐platform tool producing high‐quality maps and figures, it is used by tens of thousands of scientists ...around the world. The basic syntax of GMT scripts has evolved very slowly since the 1990s, despite the fact that GMT is generally perceived to have a steep learning curve with many pitfalls for beginners and experienced users alike. Reducing these pitfalls means changing the interface, which would break compatibility with thousands of existing scripts. With the latest GMT version 6, we solve this conundrum by introducing a new “modern mode” to complement the interface used in previous versions, which GMT 6 now calls “classic mode.” GMT 6 defaults to classic mode and thus is a recommended upgrade for all GMT 5 users. Nonetheless, new users should take advantage of modern mode to make shorter scripts, quickly access commonly used global data sets, and take full advantage of the new tools to draw subplots, place insets, and create animations.
Plain Language Summary
The Generic Mapping Tools software is widely used in Earth and ocean sciences to process data and make maps and illustrations. This new version simplifies usage, adds quick access to key data sets, and provides a tool for making scientific animations.
Key Points
A new version of the Generic Mapping Tools (GMT) is released
A new modern mode, complementing the existing classic mode, greatly simplifies GMT scripting
Easy access to remote data sets and advanced animation building facilitate science communication
We report the first plausible optical electromagnetic counterpart to a (candidate) binary black hole merger. Detected by the Zwicky Transient Facility, the electromagnetic flare is consistent with ...expectations for a kicked binary black hole merger in the accretion disk of an active galactic nucleus B. McKernan, K. E. S. Ford, I. Bartoset al., Astrophys. J. Lett.884, L50 (2019) and is unlikely <O(0.01%)) due to intrinsic variability of this source. The lack of color evolution implies that it is not a supernova and instead is strongly suggestive of a constant temperature shock. Other false-positive events, such as microlensing ora tidal disruption event, are ruled out or constrained to be <O(0.1%). If the flare is associated withS190521g, we find plausible values of total mass M(BBH) ∼ 100 Mꙩ, kick velocity v(k) ∼ 200 km/s at θ ∼ 60° in a disk with aspect ratio H/a ∼ 0.01(i.e., disk height H at radius a) and gas density ρ ∼ 10^(−10)g/cu.cm. The merger could have occurred at a disk migration trap (a ∼ 700 r(g); r(g) ≡ GM(SMBH)/sq.c, where M(SMBH) is the mass of the active galactic nucleus supermassive black hole). The combination of parameters implies a significant spin for at least one of the black holes in S190521g. The timing of our spectroscopy prevents useful constraints on broad-line asymmetry due to an off-center flare. We predict a repeat flare in this source due to a reencountering with the disk in ∼ 1.6 yr(M(SMBH)/10^(8) Mꙩ)(a/10^(3)r(g))^(3/2).
The recently commissioned Linac Coherent Light Source is an X-ray free-electron laser at the SLAC National Accelerator Laboratory. It produces coherent soft and hard X-rays with peak brightness ...nearly ten orders of magnitude beyond conventional synchrotron sources and a range of pulse durations from 500 to <10 fs (10-15 s). With these beam characteristics this light source is capable of imaging the structure and dynamics of matter at atomic size and timescales. The facility is now operating at X-ray wavelengths from 22 to 1.2 A and is presently delivering this high-brilliance beam to a growing array of scientific researchers. We describe the operation and performance of this new 'fourth-generation light source'.
The West Antarctic Ice Sheet is one of the largest potential sources of rising sea levels. Over the past 40 years, glaciers flowing into the Amundsen Sea sector of the ice sheet have thinned at an ...accelerating rate, and several numerical models suggest that unstable and irreversible retreat of the grounding line-which marks the boundary between grounded ice and floating ice shelf-is underway. Understanding this recent retreat requires a detailed knowledge of grounding-line history, but the locations of the grounding line before the advent of satellite monitoring in the 1990s are poorly dated. In particular, a history of grounding-line retreat is required to understand the relative roles of contemporaneous ocean-forced change and of ongoing glacier response to an earlier perturbation in driving ice-sheet loss. Here we show that the present thinning and retreat of Pine Island Glacier in West Antarctica is part of a climatically forced trend that was triggered in the 1940s. Our conclusions arise from analysis of sediment cores recovered beneath the floating Pine Island Glacier ice shelf, and constrain the date at which the grounding line retreated from a prominent seafloor ridge. We find that incursion of marine water beyond the crest of this ridge, forming an ocean cavity beneath the ice shelf, occurred in 1945 (±12 years); final ungrounding of the ice shelf from the ridge occurred in 1970 (±4 years). The initial opening of this ocean cavity followed a period of strong warming of West Antarctica, associated with El Niño activity. Thus our results suggest that, even when climate forcing weakened, ice-sheet retreat continued.
The Whole Atmosphere Community Climate Model version 6 (WACCM6) is a major update of the whole atmosphere modeling capability in the Community Earth System Model (CESM), featuring enhanced physical, ...chemical and aerosol parameterizations. This work describes WACCM6 and some of the important features of the model. WACCM6 can reproduce many modes of variability and trends in the middle atmosphere, including the quasi‐biennial oscillation, stratospheric sudden warmings, and the evolution of Southern Hemisphere springtime ozone depletion over the twentieth century. WACCM6 can also reproduce the climate and temperature trends of the 20th century throughout the atmospheric column. The representation of the climate has improved in WACCM6, relative to WACCM4. In addition, there are improvements in high‐latitude climate variability at the surface and sea ice extent in WACCM6 over the lower top version of the model (CAM6) that comes from the extended vertical domain and expanded aerosol chemistry in WACCM6, highlighting the importance of the stratosphere and tropospheric chemistry for high‐latitude climate variability.
Plain Language Summary
This manuscript describes the Whole Atmosphere Community Climate Model Version 6 (WACCM6), a chemistry and climate model which extends up to 140 km in the upper atmosphere. WACCM6 reproduces many important features of the climate system, and the addition of detailed chemistry and the higher than normal model top produces slightly improved simulations of the Arctic region.
Key Points
WACCM6 is a major upgrade to previous versions
WACCM6 can reproduce many modes of variability and trends in the middle atmosphere
WACCM6 provides improvements in high‐latitude climate variability at the surface and sea ice extent over a low top model
Background
Retroperitoneal sarcoma comprises a range of different histological subtypes with dissimilar behaviour and biology. This study sought to characterize the morbidity and mortality associated ...with multivisceral resection and oncological outcomes according to subtype.
Methods
All patients undergoing resection of primary retroperitoneal sarcoma at the Royal Marsden Hospital between January 2005 and December 2014 were identified from a database.
Results
Some 362 patients underwent resection, with 292 requiring multivisceral resection. The 30‐day mortality rate was 1·4 per cent (5 patients), the 30‐day morbidity rate was 15·7 per cent (57 patients), and 27 patients required a return to theatre. Age over 75 years was predictive of 30‐day mortality (hazard ratio 1·37, 95 per cent c.i. 1·13 to 1·65). The overall disease‐specific survival rate at 3 years was 81·2 per cent. For well differentiated liposarcoma, dedifferentiated liposarcoma and leiomyosarcoma, 3‐year local recurrence‐free survival rates were 98 (95 per cent c.i. 83 to 99), 56·7 (45·7 to 66·2) and 80 (67 to 89) per cent respectively. At 3 years the distant metastasis‐free survival rate was 100, 85·9 (77·4 to 91·4) and 65 (49 to 77) per cent, and the disease‐specific survival rate was 97 (89 to 99), 78·5 (74·6 to 82·4) and 79 (63 to 85) per cent for well differentiated liposarcoma, dedifferentiated liposarcoma and leiomyosarcoma respectively.
Conclusion
Resection of retroperitoneal sarcoma was associated with a 30‐day mortality rate of less than 2 per cent and a morbidity rate of 15·7 per cent. The overall 3‐year disease‐specific survival rate was 81·2 per cent.
Treatment at specialized units is preferred
In a phase III trial in patients with advanced, well-differentiated, progressive pancreatic neuroendocrine tumors, sunitinib 37.5 mg/day improved investigator-assessed progression-free survival (PFS) ...versus placebo (11.4 versus 5.5 months; HR, 0.42; P < 0.001). Here, we present PFS using retrospective blinded independent central review (BICR) and final median overall survival (OS), including an assessment highlighting the impact of patient crossover from placebo to sunitinib.
In this randomized, double-blind, placebo-controlled study, cross-sectional imaging from patients was evaluated retrospectively by blinded third-party radiologists using a two-reader, two-time-point lock, followed by a sequential locked-read, batch-mode paradigm. OS was summarized using the Kaplan–Meier method and Cox proportional hazards model. Crossover-adjusted OS effect was derived using rank-preserving structural failure time (RPSFT) analyses.
Of 171 randomized patients (sunitinib, n = 86; placebo, n = 85), 160 (94%) had complete scan sets/time points. By BICR, median (95% confidence interval CI) PFS was 12.6 (11.1–20.6) months for sunitinib and 5.8 (3.8–7.2) months for placebo (HR, 0.32; 95% CI 0.18–0.55; P = 0.000015). Five years after study closure, median (95% CI) OS was 38.6 (25.6–56.4) months for sunitinib and 29.1 (16.4–36.8) months for placebo (HR, 0.73; 95% CI 0.50–1.06; P = 0.094), with 69% of placebo patients having crossed over to sunitinib. RPSFT analysis confirmed an OS benefit for sunitinib.
BICR confirmed the doubling of PFS with sunitinib compared with placebo. Although the observed median OS improved by nearly 10 months, the effect estimate did not reach statistical significance, potentially due to crossover from placebo to sunitinib.
NCT00428597.
We provide an overview of the design and capabilities of the near-infrared spectrograph (NIRSpec) onboard the
James Webb
Space Telescope. NIRSpec is designed to be capable of carrying out ...low-resolution (
R
= 30−330) prism spectroscopy over the wavelength range 0.6–5.3 μm and higher resolution (
R
= 500−1340 or
R
= 1320−3600) grating spectroscopy over 0.7–5.2 μm, both in single-object mode employing any one of five fixed slits, or a 3.1 × 3.2 arcsec
2
integral field unit, or in multiobject mode employing a novel programmable micro-shutter device covering a 3.6 × 3.4 arcmin
2
field of view. The all-reflective optical chain of NIRSpec and the performance of its different components are described, and some of the trade-offs made in designing the instrument are touched upon. The faint-end spectrophotometric sensitivity expected of NIRSpec, as well as its dependency on the energetic particle environment that its two detector arrays are likely to be subjected to in orbit are also discussed.
We present and discuss a new dataset of gridded emissions covering the historical period (1850–2000) in decadal increments at a horizontal resolution of 0.5° in latitude and longitude. The primary ...purpose of this inventory is to provide consistent gridded emissions of reactive gases and aerosols for use in chemistry model simulations needed by climate models for the Climate Model Intercomparison Program #5 (CMIP5) in support of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment report (AR5). Our best estimate for the year 2000 inventory represents a combination of existing regional and global inventories to capture the best information available at this point; 40 regions and 12 sectors are used to combine the various sources. The historical reconstruction of each emitted compound, for each region and sector, is then forced to agree with our 2000 estimate, ensuring continuity between past and 2000 emissions. Simulations from two chemistry-climate models are used to test the ability of the emission dataset described here to capture long-term changes in atmospheric ozone, carbon monoxide and aerosol distributions. The simulated long-term change in the Northern mid-latitudes surface and mid-troposphere ozone is not quite as rapid as observed. However, stations outside this latitude band show much better agreement in both present-day and long-term trend. The model simulations indicate that the concentration of carbon monoxide is underestimated at the Mace Head station; however, the long-term trend over the limited observational period seems to be reasonably well captured. The simulated sulfate and black carbon deposition over Greenland is in very good agreement with the ice-core observations spanning the simulation period. Finally, aerosol optical depth and additional aerosol diagnostics are shown to be in good agreement with previously published estimates and observations.
PDF
