Comment on “Trends and low frequency variability of extra-tropical cyclone activity in the ensemble of twentieth century reanalysis” by Xiaolan L. Wang,Y. Feng,G. P. Compo,V. R. Swail,F. W. Zwiers,R. J. Allan,and P. D. Sardeshmukh,Climate Dynamics, 2012

The main subject of this article is to comment on the issue of storminess trends derived from the twentieth century reanalysis (20CR) and from observations in the North Atlantic region written about in Wang et al. (Clim Dyn 40(11–12):2775–2800, 2012). The statement that the 20CR estimates would be consistent with storminess derived from pressure-based proxies does not hold for the time prior to 1950.     

“Reporting on climate change: A computational analysis of U.S. newspapers and sources of bias, 1997–2017”

News organizations constitute key sites of science communication between experts and lay audiences, giving many individuals their basic worldview of complex topics like climate change. Previous researchers have studied climate change news coverage to assess accuracy in reporting and potential sources of bias. These studies typically rely on manually coding articles from a handful of prestigious outlets, not allowing comparisons with smaller newspapers or providing enough diversity to assess the influence of partisan orientation or localized climate vulnerability on content production. Making these comparisons, this study indicates that partisan orientation, scale of circulation, and vulnerability to climate change correlate with several topics present in U.S. newspaper coverage of climate change. After assembling a corpus of over 78,000 articles covering two decades from 52 U.S. newspapers that are diverse in terms of geography, partisan orientation, scale of circulation, and objectively measured climate risk, a coherent set of latent topics were identified via an automated content analysis of climate change news coverage. Topic model results indicate that while outlet bias does not appear to impact the prevalence of coverage for most topics surrounding climate change, differences were evident for some topics based on partisan orientation, scale, or vulnerability status, particularly those relating to climate change denial, impacts, mitigation, or resource use. Overall, this paper provides a comprehensive study of U.S. newspaper coverage of climate change and identifies specific topics where outlet bias constitutes an important contextual factor.     

Climatology and variability of historical Soviet snow depth data: some new perspectives in snow – Indian monsoon teleconnections

 This study presents the monthly climatology and variability of the historical soviet snow depth data. This data set was developed under the bilateral data exchange agreement between United States of America and the former Union of Soviet Socialist Republics. The original data is for 284 stations for periods varying from 1881 upto 1985. The seasonal cycle of the mean snow depth has been presented both as spatial maps and as averages over key locations. The deepest snow (=80 cms/day) areas are found over Siberia (in Particular over 80′–100 ′E, 55′–70 ′N) during March. Over the course of the annual cycle average snow depth over this region changes dramatically from about 10 cms in October to about 80 cms in March. The variability is presented in the form of spatial maps of standard deviation. To investigate the interaction of snow depth with Indian monsoon rainfall (IMR), lag and lead correlation coefficients are computed. Results reveal that the winter-time snow depth over western Eurasia surrounding Moscow (eastern Eurasia in central Siberia) shows significant negative (positive) relationship with subsequent IMR. Following the monsoon the signs of relationship reverse over both the regions. This correlation structure is indicative of a midlatitude longwave pattern with an anomalous ridge (trough) over Asia during the winter prior to a strong (weak) monsoon. As the time progresses from winter to spring, the coherent areas of significant relationship show southeastward propagation. Empirical orthogonal function analysis of the snow depth reveal that the first mode describes a dipole-type structure with one centre around Moscow and the other over central Siberia, depicting similar pattern as the spatial correlation structure. The decadal-scale IMR variations seem to be more associated with the Northern Hemisphere midlatitude snow depth variations rather than with the tropical ENSO (El Nino Southern Oscillation) variability. Received: 16 March 1998 / Accepted: 24 December 1998     

Reply to comment by Ben-Zvi,A., D. Rosenfeld and A. Givati on the paper: Levin,Z., N. Halfon and P. Alpert, “Reassessment of rain experiments and operations in Israel including synoptic considerations,” Atmos. Res. 97, 513–525. DOI: 10.1016/j.atmosres.2010.06.011

Levin et al. (2010; hereafter LHA) (Levin, Z., Halfon, N., Alpert, P., 2010. Reassessment of rain experiments and operations in Israel including synoptic considerations. Atmos. Res. 97, 513–525. DOI:10.1016/j.atmosres.2010.06.011.), reanalyzed the results of the operational seeding in northern Israel between 1975 and 2007 and the preceding Israel 2 cloud seeding experiment (1969–1975) and concluded that there is no net increase in precipitation over the target areas. Our analysis revealed that a synoptic bias during Israel 2 is one of the reasons for the apparent positive effect of seeding in the northern target area and the negative effect in the southern area both of which disappeared in the following experiment in the south (Israel 3; 1975–1995) and the operational seeding in the north.Ben-Zvi et al. (2010;hereafter BRG) criticized our paper primarily on the ground that we did not consider the positive results of Israel 1 experiment (1960–1967). It should be noted that in Israel 1 different seeding lines were used from those in both Israel 2 and the operational period. In addition, its raw data is not accessible anymore for reanalysis. Furthermore, Israel 2 had been designed as a confirmatory cross-over experiment to Israel 1 and failed to reproduce its promising results with double ratio (DR) of ~ 1.00, namely, zero rainfall enhancements. The same DR values were also found in Israel 3 and in the operational seeding. Therefore, because of the differences in the two experiments, the lack of access to the raw data and the disappointing results of the confirmatory experiment, we decided to concentrate our analysis on the more recent seeding activities.The attempt by BRG to explain the reduction of the DR to ~ 1.00 in the operational seeding period by the suppression due to pollution have been disproved by Alpert et al., 2008, Alpert et al., 2009 and also fail to explain the sharp decline of the target/control ratio right at the beginning of the operational seeding period when the lucky draw in this area came to its end (see LHA).     

What (science for) adaptation to climate change in Colombian agriculture? A commentary on “A way forward on adaptation to climate change in Colombian agriculture: perspectives towards 2050” by J. Ramirez-Villegas, M. Salazar, A. Jarvis, C. E. Navarro-Valcines

Climate change is putting Colombian agriculture under significant stress and, if no adaptation is made, the latter will be severely impacted during the next decades. Ramirez-Villegas et al. (2012) set out a government-led, top-down, techno-scientific proposal for a way forward by which Colombian agriculture could adapt to climate change. However, this proposal largely overlooks the root causes of vulnerability of Colombian agriculture, and of smallholders in particular. I discuss some of the hidden assumptions underpinning this proposal and of the arguments employed by Ramirez-Villegas et al., based on existing literature on Colombian agriculture and the wider scientific debate on adaptation to climate change. While technical measures may play an important role in the adaptation of Colombian agriculture to climate change, I question whether these actions alone truly represent priority issues, especially for smallholders. I suggest that by i) looking at vulnerability before adaptation, ii) contextualising climate change as one of multiple exposures, and iii) truly putting smallholders at the centre of adaptation, i.e. to learn about and with them, different and perhaps more urgent priorities for action can be identified. Ultimately, I argue that what is at stake is not only a list of adaptation measures but, more importantly, the scientific approach from which priorities for action are identified. In this respect, I propose that transformative rather than technical fix adaptation represents a better approach for Colombian agriculture and smallholders in particular, in the face of climate change.     

A “precariously unprepared” Pentagon? Climate security beliefs and decision-making in the U.S. military

Increasing evidence suggests that climate change poses direct and indirect threats to national and human security. However, the degree to which such knowledge of the risks informs decision-making remains poorly understood for key security communities, including the U.S. Department of Defense. Here, through document analysis and interviews with climate security researchers and practitioners from the U.S. military community, we evaluate perceptions about and the degree to which (i) these individuals believe climate change is a threat to U.S. national security interests, and (ii) the U.S. Department of Defense integrates climate security science into its decision-making. Our research suggests a complex answer. Public statements and reports indicate U.S. Department of Defense leadership considers climate change a security threat of strategic importance, and most researchers interviewed believe the U.S. Department of Defense prioritizes climate security as a near-term threat. However, evidence of climate security threats is only selectively integrated into planning and decision-making. Interviews suggest several barriers and enablers to evidence-based decision-making within the U.S. Department of Defense. Barriers include mixed beliefs in the near-term urgency of the threat, changing political environments, and insufficient co-production of actionable science across the levels of war, including issues of data collection, sharing, and analysis. Enablers include increased awareness after climate-related impacts, strong leadership support, and knowledge transfer and convening forums. Improved insight into the production and use of climate security knowledge is crucial for the task of safeguarding human and national security in a changing climate.     

The asymmetric effects of fossil fuel dependency on the carbon intensity of well-being: A U.S. state-level analysis, 1999–2017

The resource dependency literature argues that intensifying processes of dependency can lead to poorer socioecological outcomes, but the effects of reducing dependency remain untested. Some scholars argue that it improves socioecological conditions, while other strands of research suggest that it causes economic hardship, as evidenced by the deaths of despair crisis. Here, I examine the asymmetric effects of fossil fuel dependency (measured as the energy production-consumption ratio, the share of exports from the mining sector, and the share of GDP from the mining sector) on the carbon intensity of well-being (CIWB) at the U.S. state-level. I do so by estimating dynamic asymmetric models with fixed effects estimation. I find that increases in all three measures are associated with increases in the CIWB. Decreases in the energy production-consumption ratio and the share of exports from the mining sector do not affect the CIWB, while a decrease in the share of GDP from the mining sector produces a proportional reduction in the CIWB relative to an increase. The estimated net effect of all three variables suggests that an increase in fossil fuel dependency increases the CIWB, while a decrease has no effect. When the CIWB is disaggregated, I find that changes in the energy production-consumption ratio are driving changes in emissions and that changes in the share of GDP from the mining sector are responsible for changes in health-adjusted life expectancy. Given that the net effect of a decrease in fossil fuel dependency is not statistically significant, I conclude by arguing that a planned, managed transition away from fossil fuel extraction is critical to ensuring simultaneous improvements in human and environmental well-being.     

(九)A.I.D.的作图法

本讲介绍如何在图上进行A.I.D.的分类筛选预报,它的优点是避免了计算,利用和天气预报中常用的点聚图方法相类似的画法,就可以作出预报。现用一个实例来说明。 考虑长江中下游汉口、九江、芜湖、南京、上海五站平均5—8月降水总量(y),选用了1952—1976年25年资料用五个气象要素作为因子。 因子:x_1是一月0—150°E,45—65°N的纬向指数I_z, x_2是一月份欧洲大型环流型C型天数, x_3是一月份长江流域六站降水量∑R_1月, x_4是一月份长江流域六站温度∑月,     

(八)A.I.D.方法的一般理论

第七讲的方法,如果不是用极差进行分割,而是用变差进行分割,就成为一般书上所说的A.I.D.方法(筛选因子的一个新方法)。实际上,A.I.D.方法仅仅是最优分割法的一种灵活运用。为了能比较清楚地说明这一点,我们就依照一般书上的写法来介绍A.I.D.方法,然后,再说明它与最优分割法的关系。     

Dynamical and Thermal Problems in Vortex Development and Movement. Part I: A PV–Q View

Based on the Lagrangian change equation of vertical vorticity deduced from the equation of threedimensional Ertel potential vorticity(PV e),the development and movement of vortex are investigated from the view of potential vorticity and diabatic heating(PV-Q).It is demonstrated that the asymmetric distribution in the vortex of the non-uniform diabatic heating in both vertical and horizontal can lead to the vortex’s development and movement.The theoretical results are used to analyze the development and movement of a Tibetan Plateau(TP) vortex(TPV),which appeared over the TP,then slid down and moved eastward in late July 2008,resulting in heavy rainfall in Sichuan Province and along the middle and lower reaches of the Yangtze River.The relative contributions to the vertical vorticity development of the TPV are decomposed into three parts:the diabatic heating,the change in horizontal component of PV e(defined as PV 2),and the change in static stability θ z.The results show that in most cases,diabatic heating plays a leading role,followed by the change in PV 2,while the change of θ z usually has a negative impact in a stable atmosphere when the atmosphere becomes more stable,and has a positive contribution when the atmosphere approaches neutral stratification.The intensification of the TPV from 0600 to 1200 UTC 22 July 2008 is mainly due to the diabatic heating associated with the precipitation on the eastern side of the TPV when it uplifted on the up-slope of the northeastern edge of the Sichuan basin.The vertical gradient of diabatic heating makes positive(negative) PV e generation below(above) the maximum of diabatic heating;the positive PV e generation not only intensifies the low-level vortex but also enhances the vertical extent of the vortex as it uplifts.The change in PV e due to the horizontal gradient of diabatic heating depends on the vertical shear of horizontal wind that passes through the center of diabatic heating.The horizontal gradient of diabatic heating makes positive(negative) PV e generation on the right(left) side of the vertical shear of horizontal wind.The positive PV e generation on the right side of the vertical shear of horizontal wind not only intensifies the local vertical vorticity but also affects direction of movement of the TPV.These diagnostic results are in good agreement with the theoretic results developed from the PV-Q view.