Biases in the albedo sensitivity to deforestation in CMIP5 models and their impacts on the associated historical radiative forcing

Climate model biases in the representation of albedo variations between land cover classes contribute to uncertainties on the climate impact of land cover changes since pre-industrial times, especially on the associated radiative forcing. Recent publications of new observation-based datasets offer opportunities to investigate these biases and their impact on historical surface albedo changes in simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Conducting such an assessment is, however, complicated by the non-availability of albedo values for specific land cover classes in CMIP and the limited number of simulations isolating the land use forcing. In this study, we demonstrate the suitability of a new methodology to extract the albedo of trees and crops–grasses in standard climate model simulations. We then apply it to historical runs from 17 CMIP5 models and compare the obtained results to satellite-derived reference data. This allows us to identify substantial biases in the representation of the albedo of trees and crops–grasses as well as the surface albedo change due to the transition between these two land cover classes in the analysed models. Additionally, we reconstruct the local surface albedo changes induced by historical conversions between trees and crops–grasses for 15 CMIP5 models. This allows us to derive estimates of the albedo-induced radiative forcing from land cover changes since pre-industrial times. We find a multi-model range from 0 to −0.17 W m−2, with a mean value of −0.07 W m−2. Constraining the surface albedo response to transitions between trees and crops–grasses from the models with satellite-derived data leads to a revised multi-model mean estimate of −0.09 W m−2 but an increase in the multi-model range. However, after excluding one model with unrealistic conversion rates from trees to crops–grasses the remaining individual model results vary between −0.03 and −0.11 W m−2. These numbers are at the lower end of the range provided by the IPCC AR5 (−0.15±0.10 W m−2). The approach described in this study can be applied to other model simulations, such as those from CMIP6, especially as the evaluation diagnostic described here has been included in the ESMValTool v2.0

Potential vorticity anomalies related to clouds and precipitation in extratropical cyclones

Different microphysical processes influence the dynamics of cyclones by their associated latent heating or cooling, which modifies potential vorticity (PV) from the boundary layer to slightly above the tropopause level. A new method is developed based on integrating diabatic PV changes along backward trajectories. This method allows us to decompose the Lagrangian PV change over a certain time interval into contributions from different microphysical processes, including the below-cloud processes snow sublimation, snow melting and rain evaporation. The method is first applied to an extratropical cyclone in an idealized baroclinic channel setup. The mesoscale PV structure along the bent-back front results from a complex combination of microphysical processes. The microphysical contributions to the different positive and negative anomalies are analyzed in detail. It is found that for each anomaly, typically one specific microphysical process takes the leading role in its diabatic generation. A large but rather weak low and mid-level positive anomaly is produced by depositional growth of ice and snow. Two smaller but stronger positive anomalies at lower levels are generated mainly by in-cloud condensational heating at the warm front, and below-cloud rain evaporation and snow melting 200 km further north. In addition, near-surface negative anomalies are produced by snow melting and snow sublimation, respectively. The same method is applied to a particularly strong maritime extratropical cyclone, occurring over the Bering Sea on 12-14 December 2015. The warm-frontal structure is characterized by one strong positive PV anomaly stretching from the surface almost up to the tropopause. For this anomaly, condensation and below-cloud rain evaporation contribute most in the lower part, whereas deposition of ice and snow are more important in the upper part. Snow melting contributes very strongly in a localized region at the surface front. Snow sublimation leads to a weak negative anomaly on the cold side of the front. The cold frontal structure was found to be characterized by two strong low-level positive PV anomalies. The one on the warm side is produced due to condensation and below-cloud rain evaporation, the one on the cold side, located outside the clouds, has contributions from almost all microphysical processes. The time evolution of the anomalies showed that positive anomalies vary most over time, whereas negative anomalies stay relatively constant. The transition of the cyclone to a situation where it is embedded in a colder environment is marked by an increasing relative importance of the ice-phase processes compared to the liquid phase processes. The general findings of this study are: (a) a complex combination of microphysical processes dictates the strength and structure of diabatic PV anomalies along the fronts; (b) below-cloud processes are relevant for both the positive and negative anomalies throughout most of the troposphere; and (c) the Lagrangian approach proved meaningful for this detailed process-based analysis of dynamically relevant mesoscale flow structures. With regard to the below-cloud process, we note their strong contributions up to 1.0 PVU to the positive low-level anomalies, their relevance for anomalies in both the warm sector (mainly rain evaporation) and the cold sector (mainly rain evaporation and snow sublimation), and the importance of snow melting in localized regions close to the surface front. Furthermore, it is shown that in the mid troposphere both the integrated diabatic PV tendencies (Lagrangian anomalies) and consideration of cross-isentropic transport in a background with a vertical PV gradient are important to understand the resulting PV anomalies. Idealized modelling has the potential to further distinguish the inherently linked effects of Lagrangian PV modification and cross-isentropic transport of low-PV air. Finally, it is shown how our novel method could lead to a better understanding of the pathways of stratosphere-troposphere exchange and the involved physical processes

The complex life cycles of two long-lived potential vorticity cut-offs over Europe

ISSN:0035-9009ISSN:1477-870

Biases in the albedo sensitivity to deforestation in CMIP5 models and their impacts on the associated historical radiative forcing

Climate model biases in the representation of albedo variations between land cover classes contribute to uncertainties on the climate impact of land cover changes since pre-industrial times, especially on the associated radiative forcing. Recent publications of new observation-based datasets offer opportunities to investigate these biases and their impact on historical surface albedo changes in simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Conducting such an assessment is, however, complicated by the non-availability of albedo values for specific land cover classes in CMIP and the limited number of simulations isolating the land use forcing. In this study, we demonstrate the suitability of a new methodology to extract the albedo of trees and crops–grasses in standard climate model simulations. We then apply it to historical runs from 17 CMIP5 models and compare the obtained results to satellite-derived reference data. This allows us to identify substantial biases in the representation of the albedo of trees and crops–grasses as well as the surface albedo change due to the transition between these two land cover classes in the analysed models. Additionally, we reconstruct the local surface albedo changes induced by historical conversions between trees and crops–grasses for 15 CMIP5 models. This allows us to derive estimates of the albedo-induced radiative forcing from land cover changes since pre-industrial times. We find a multi-model range from 0 to −0.17 W m−2, with a mean value of −0.07 W m−2. Constraining the surface albedo response to transitions between trees and crops–grasses from the models with satellite-derived data leads to a revised multi-model mean estimate of −0.09 W m−2 but an increase in the multi-model range. However, after excluding one model with unrealistic conversion rates from trees to crops–grasses the remaining individual model results vary between −0.03 and −0.11 W m−2. These numbers are at the lower end of the range provided by the IPCC AR5 (−0.15±0.10 W m−2). The approach described in this study can be applied to other model simulations, such as those from CMIP6, especially as the evaluation diagnostic described here has been included in the ESMValTool v2.0.ISSN:2190-4987ISSN:2190-497

Three-dimensional controlled interstitial hyperthermia combined with radiotherapy for locally advanced prostate carcinoma--a feasibility study

To perform a feasibility study of three-dimensional spatially controlled interstitial hyperthermia for locally advanced prostate cancer. Twelve patients with prostate cancer (T3NxM0) were treated with conventional external beam radiotherapy and one interstitial hyperthermia treatment. Hyperthermia was delivered with the 27-MHz multielectrode current source (MECS) interstitial hyperthermia technique on an outpatient basis. Guided by transrectal ultrasonography, 12 catheters (range 7-16) were placed in the prostate through a template. Two electrodes per probe were inserted. Thermometry (average 100 sensors) was performed from within the probes for online temperature control. Additional thermometry was done in the prostate, rectum, urethra, and bladder. Reconstruction was done by sonography. Prostate perfusion was estimated from the thermal decay at the end of treatment. The full three-dimensional temperature distribution was calculated. No toxicities greater than Grade 2 were recorded. A learning curve for implantation, position verification, reconstruction, and temperature simulation was experienced. Perfusion was 47 mL/100 g/min (range 30-65). The average measured temperature was T(90) (90% of the prostate reached a temperature of at least:) 39.9 degrees C and T(50) 44.1 degrees C. The average calculated temperatures were lower: T(90), 39.4 degrees C and T(50), 41.8 degrees C, because the entire prostate was taken into account. The tumor temperatures were T(90), 40.7 degrees C and T(50), 43.0 degrees C. The bladder and rectal temperatures were below the safety limits. Multielectrode-current-source interstitial hyperthermia is technically feasible and well tolerated. It was not possible to achieve the goal temperature of 42-43 degrees C because of high perfusion and implantation limitation

Independent Quality Assessment of Essential Climate Variables: Lessons learnt from the Copernicus Climate Change Service

If climate services are to lead to effective use of climate information in decision-making to enable the transition to a climate-smart, climate-ready world, then the question of trust in the products and services is of paramount importance. The Copernicus Climate Change Service (C3S) has been actively grappling with how to build such trust: provision of demonstrably independent assessments of the quality of products, which was deemed an important element in such trust-building processes. C3S provides access to essential climate variables (ECVs) from multiple sources to a broad set of users ranging from scientists to private companies and decision-makers. Here we outline the approach undertaken to coherently assess the quality of a suite of observation- and reanalysis-based ECV products covering the atmosphere, ocean, land, and cryosphere. The assessment is based on four pillars: basic data checks, maturity of the datasets, fitness for purpose (scientific use cases and climate studies), and guidance to users. It is undertaken independently by scientific experts and presented alongside the datasets in a fully traceable, replicable, and transparent manner. The methodology deployed is detailed, and example assessments are given. These independent scientific quality assessments are intended to guide users to ensure they use tools and datasets that are fit for purpose to answer their specific needs rather than simply use the first product they alight on. This is the first such effort to develop and apply an assessment framework consistently to all ECVs. Lessons learned and future perspectives are outlined to potentially improve future assessment activities and thus climate services.ISSN:0003-0007ISSN:1520-047

Independent Quality Assessment of Essential Climate Variables: Lessons Learned from the Copernicus Climate Change Service

If climate services are to lead to effective use of climate information in decision-making to enable the transition to a climate-smart, climate-ready world, then the question of trust in the products and services is of paramount importance. The Copernicus Climate Change Service (C3S) has been actively grappling with how to build such trust: provision of demonstrably independent assessments of the quality of products, which was deemed an important element in such trust-building processes. C3S provides access to essential climate variables (ECVs) from multiple sources to a broad set of users ranging from scientists to private companies and decision-makers. Here we outline the approach ­undertaken to coherently assess the quality of a suite of observation- and reanalysis-based ECV products covering the atmosphere, ocean, land, and cryosphere. The assessment is based on four pillars: basic data checks, maturity of the datasets, fitness for purpose (scientific use cases and climate studies), and guidance to users. It is undertaken independently by scientific experts and presented alongside the datasets in a fully traceable, replicable, and transparent manner. The methodology deployed is detailed, and example assessments are given. These independent scientific quality assessments are intended to guide users to ensure they use tools and datasets that are fit for purpose to answer their specific needs rather than simply use the first product they alight on. This is the first such effort to develop and apply an assessment framework consistently to all ECVs. Lessons learned and future perspectives are outlined to potentially improve future assessment activities and thus climate services.This work is funded by European Copernicus Climate Change Service (C3S) implemented by European Centre for Medium-Range Weather Forecasts (ECMWF) under the service contract Independent Assessment on ECVs led by the National Research Council of Italy (CNR) with the service contract number as ECMWF/Copernicus/2017/C3S_511_CNR.Peer reviewe

Earth System Model Evaluation Tool (ESMValTool) v2.0-an extended set of large-scale diagnostics for quasi-operational and comprehensive evaluation of Earth system models in CMIP

The Earth System Model Evaluation Tool (ESMValTool) is a community diagnostics and performance metrics tool designed to improve comprehensive and routine evaluation of Earth system models (ESMs) participating in the Coupled Model Intercomparison Project (CMIP). It has undergone rapid development since the first release in 2016 and is now a well-tested tool that provides end-to-end provenance tracking to ensure reproducibility. It consists of (1) an easy-to-install, well-documented Python package providing the core functionalities (ESMValCore) that performs common preprocessing operations and (2) a diagnostic part that includes tailored diagnostics and performance metrics for specific scientific applications. Here we describe large-scale diagnostics of the second major release of the tool that supports the evaluation of ESMs participating in CMIP Phase 6 (CMIP6). ESMValTool v2.0 includes a large collection of diagnostics and performance metrics for atmospheric, oceanic, and terrestrial variables for the mean state, trends, and variability. ESMValTool v2.0 also successfully reproduces figures from the evaluation and projections chapters of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) and incorporates updates from targeted analysis packages, such as the NCAR Climate Variability Diagnostics Package for the evaluation of modes of variability, the Thermodynamic Diagnostic Tool (TheDiaTo) to evaluate the energetics of the climate system, as well as parts of AutoAssess that contains a mix of top-down performance metrics. The tool has been fully integrated into the Earth System Grid Federation (ESGF) infrastructure at the Deutsches Klimarechenzentrum (DKRZ) to provide evaluation results from CMIP6 model simulations shortly after the output is published to the CMIP archive. A result browser has been implemented that enables advanced monitoring of the evaluation results by a broad user community at much faster timescales than what was possible in CMIP5.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

ESMValTool

ESMValTool: A community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP

Adjuvant hyperthermic intraperitoneal chemotherapy in patients with locally advanced colon cancer (COLOPEC): a multicentre, open-label, randomised trial

Background: Nearly a quarter of patients with locally advanced (T4 stage) or perforated colon cancer are at risk of developing peritoneal metastases, often without curative treatment options. We aimed to determine the efficacy of adjuvant hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with locally advanced colon cancer. Methods: This multicentre, open-label trial was done in nine hospitals that specialised in HIPEC in the Netherlands. Patients with clinical or pathological T4N0–2M0-stage tumours or perforated colon cancer were randomly assigned (1:1), with a web-based randomisation application, before resection of the primary tumour, to adjuvant HIPEC followed by routine adjuvant systemic chemotherapy (experimental group) or to adjuvant systemic chemotherapy alone (control group). Patients were stratified by tumour characteristic (T4 or perforation), age (<65 years or ≥65 years), and surgical approach of the primary tumour resection (laparoscopic or open). Key eligibility criteria included age between 18 and 75 years, adequate clinical condition for HIPEC, and intention to start adjuvant systemic chemotherapy. Patients with metastatic disease were ineligible. Adjuvant HIPEC consisted of fluorouracil (400 mg/m2) and leucovorin (20 mg/m2) delivered intravenously followed by intraperitoneal delivery of oxaliplatin (460 mg/m2) for 30 min at 42°C, delivered simultaneously or within 5–8 weeks after primary tumour resection. In all patients without evidence of recurrent disease at 18 months, a diagnostic laparoscopy was done. The primary endpoint was peritoneal metastasis free-survival at 18 months, measured in the intention-to-treat population, with the Kaplan-Meier method. Adverse events were assessed in all patients who received assigned treatment. This study is registered with ClinicalTrials.gov, number NCT02231086. Findings: Between April 1, 2015, and Feb 20, 2017, 204 patients were randomly assigned to treatment (102 in each group). In the HIPEC group, two patients withdrew consent after randomisation. In this group, 19 (19%) of 100 patients were diagnosed with peritoneal metastases: nine (47%) during surgical exploration preceding intentional adjuvant HIPEC, eight (42%) during routine follow-up, and two (11%) during diagnostic laparoscopy at 18-months. In the control group, 23 (23%) of 102 patients were diagnosed with peritoneal metastases, of whom seven (30%) were diagnosed by laparoscopy at 18-months and 16 during regular follow-up (therefore making them ineligible for diagnostic laparoscopy). In the intention-to-treat analysis (n=202), there was no difference in peritoneal-free survival at 18-months (80·9% [95% CI 73·3–88·5] for the experimental group vs 76·2% [68·0–84·4] for the control group, log-rank one-sided p=0·28). 12 (14%) of 87 patients who received adjuvant HIPEC developed postoperative complications and one (1%) encapsulating peritoneal sclerosis. Interpretation: In patients with T4 or perforated colon cancer, treatment with adjuvant HIPEC with oxaliplatin did not improve peritoneal metastasis-free survival at 18 months. Routine use of adjuvant HIPEC is not advocated on the basis of this trial. Funding: Organization for Health Research and Development and the Dutch Cancer Society