Periodic Shifts Research Articles

Climate change impact on hydrological characteristics and water availability of the Mountain Pamir Rivers

Abstract. Results of monitoring accumulated snow cover in upstream areas of the Transboundary Pyanj River (Central Asia) are presented. It is found that the formation of the snow cover and the spatial distribution of atmospheric precipitation in the Mountain Pamir is determined by the orography of the terrain. Orography influences air mass movement in mountain areas, which contributes in different climatic zones to a shift in periods when the maximum amount of snow is falling. Completely different scenarios for the development of meteorological variables in the western and eastern parts of the Gunt River Basin were found, due, firstly, to the influence of the mountainous area orography and, secondly, to the penetration of various air masses. It is observed that in the western part of the basin the average annual precipitation remained almost unchanged over the period 1944–2014, whereas there is a decreasing trend in the eastern part. Assessment of the climate change impact on the formation of the Gunt River water flow was made by comparing the trend in the change of discharge using data from two observation periods 1940–1970 and 1986–2016. Calculations show a decrease of the Gunt River discharge by 5 % over a period of more than 70 years. The influence of climate warming on the river flow is indicated by comparison of river hydrograph in two periods 1940–1970 and 1986–2016. The hydrograph of the Vanch River in the earlier-mentioned periods shows a shift in the maximum of the monthly discharge towards the left, indicating an earlier melting of snow and glaciers in the upstream regions of the river and a significant increase in discharge in the period 1986–2016.

Quasi-periodic waves and irregular solitary waves of the AB system

Investigated in this paper is the AB system, which is used to describe the baroclinic instability processes in the geophysical flows. By introducing an auxiliary function , we construct the quasi-periodic wave solutions of the AB system, and find that behaviors of the quasi-periodic waves are similar to those of the periodic waves of the AB system except for certain phase shift in each evolution period. Especially, when , the quasi-periodic waves develop into the periodic waves. Besides, it is found that under certain conditions the quasi-periodic waves degenerate into the irregular solitary waves, which are characterized by shape variations or appearances, splits, combinations and disappearances of certain bulges in the evolution.

Periodic Genotype Shifts in Clinically Prevalent Mycoplasma pneumoniae Strains in Japan.

Nationwide increases in Mycoplasma pneumoniae pneumonia cases in Japan were reported in 2011, 2012, 2015, and 2016. In this study, we isolated 554 M. pneumoniae strains in 4 areas in Japan (Kanagawa, Okayama, Osaka, and Saitama) between 2006 and 2019, and performed genotyping analysis. More than 80% of the strains isolated in 2011 and 2012 harbored type 1 p1 adhesin gene; however, strains harboring type 2 or its variant p1 gene increased in 2015 and 2016 and dominated after 2017. These findings suggested that a shift in the prevalent genotype of M. pneumoniae clinical strains occurred recently in Japan. More than 90% of the type 1 strains isolated after 2010 harbored macrolide-resistance mutations in their 23S rRNA gene, whereas most type 2 lineage strains had no such mutations. Consequently, the increase in type 2 lineage strains in Japan has reduced the macrolide resistance rate of clinical M. pneumoniae strains. During this analysis, we also identified M. pneumoniae strains carrying a novel variant type 1 p1 gene, and we classified it as type 1b. We then sequenced the genomes of 81 selected M. pneumoniae strains that we collected between 1976 and 2017 in Japan, and compared them with 156 M. pneumoniae genomes deposited in public databases to provide insights into the interpretation of M. pneumoniae genotyping methods, including p1 typing, multiple-locus variable-number tandem repeat analysis (MLVA), multi-locus sequence typing (MLST), and typing by 8 single-nucleotide polymorphism markers (SNP-8). As expected, p1 typing, MLST, and SNP-8 results exhibited good correlation with whole-genome SNP analysis results in terms of phylogenetic relationships; however, MLVA typing results were less comparable to those of the other methods. MLVA may be useful for the discrimination of strains derived from a single outbreak within a limited area; however, is not reliable for classification of strains collected from distantly separated areas at different time points. This study showed the usefulness of genome-based comparison of M. pneumoniae for molecular epidemiology. Genome sequencing of more strains will improve our understanding of global propagation routes of this pathogen and evolutionary aspects of M. pneumoniae strains.

Analysis of Phonon Modes and Electron–Phonon Interaction in Quantum-Cascade Laser Heterostructures

The phonon modes of quantum-cascade heterostructures based on binary and ternary semiconductor compounds are simulated. The dependences of the frequencies of the structure interface phonon modes on the wave vector in the layer plane and on the phase shift in the superlattice period are calculated. It is found that the range of variation in the quantum energy of phonon modes of the GaAs/Al0.25Ga0.75As structure does not exceed 2 meV. The calculated resulting interband scattering rate in the structure, taking into account the interface and confined modes, barely differs from that calculated in the bulk phonon approximation.

Rising temperature and marine plankton community dynamics: Is warming bad?

Global warming is a major threat to the natural environment worldwide with potential adverse impact on plankton community. This will ultimately lead to a change in the dynamics of aquatic food webs. In this study we used seasonally forced multi-species version of the classic Rosenzweig–MacArthur predator–prey model to understand the role and stochastic influence of increasing temperature on marine plankton. First, stable coexistence of four phytoplankton and three zooplankton species was created in a system and then the level of temperature changed to achieve our research goal. We found that the stable coexistence of phytoplankton and zooplankton was related to periodic shifts in species biomass, variation in inter-specific competition and niche configuration. Warming significantly reduced total plankton biomass and changed turnover time of a species, with gradual warming breaking the stable coexistence of phytoplankton and zooplankton. In addition, we found that warming make specialist species more vulnerable than generalist species. After adding noise, a significant variation was observed in plankton biomass and amplification of noise was higher for phytoplankton compared to zooplankton. These results suggest that stochastic or unpredictable nature of temperature fluctuations may create a window of opportunity for the emergence of new species. Overall, warming would induce a shift in plankton dynamics and thereby exert pressure on plankton dependent communities such as fish in the long run.

Prolonged Periodicity and Eastward Shift of the January North Pacific Oscillation Since the Mid‐1990s and Its Linkage With Sea Ice Anomalies in the Barents Sea

AbstractThe present study mainly investigates changes in the periodicity and location of the January North Pacific Oscillation (NPO) and the underlying mechanisms during 1980–2018. The periodicity of the January NPO prolongs from 2–3 years to 5–8 years around the mid‐1990s. Corresponding to the prolonged periodicity, both the southern and northern lobes of the January NPO shift eastward, and their meridional movement is relatively weak. As a result, the impacts of the January NPO on surface air temperature in North America are enhanced. The changes in the periodicity and location of the January NPO differ from those of the NPO of other winter months. Further study shows that the changes in the January NPO are closely related to the sea ice anomalies in the Barents Sea in the preceding November‐December and January. The sea ice anomalies also display a periodicity of 5–8 years after the mid‐1990s, and their impacts on the January NPO are enhanced. The January NPO is significantly and negatively correlated with the sea ice anomalies after the mid‐1990s. The sea ice anomalies contribute to the prolonged periodicity and eastward shift of the January NPO by exciting a quasi‐stationary Rossby wave propagating eastward along the coast of northern Eurasia and resultant atmospheric dynamic processes. The physical mechanism is reasonably reproduced by the numerical experiment with observed sea ice anomalies in the Barents Sea prescribed. In addition, possible reasons for the enhanced impacts of the sea ice anomalies on the January NPO are discussed.

Metabolic Effects of Late Dinner in Healthy Volunteers-A Randomized Crossover Clinical Trial.

Consuming calories later in the day is associated with obesity and metabolic syndrome. We hypothesized that eating a late dinner alters substrate metabolism during sleep in a manner that promotes obesity. The objective of this work is to examine the impact of late dinner on nocturnal metabolism in healthy volunteers. This is a randomized crossover trial of late dinner (LD, 22:00) vs routine dinner (RD, 18:00), with a fixed sleep period (23:00-07:00) in a laboratory setting. Participants comprised 20 healthy volunteers (10 male, 10 female), age 26.0 ± 0.6 years, body mass index 23.2 ± 0.7 kg/m2, accustomed to a bedtime between 22:00 and 01:00. An isocaloric macronutrient diet was administered on both visits. Dinner (35% daily kcal, 50% carbohydrate, 35% fat) with an oral lipid tracer ([2H31] palmitate, 15 mg/kg) was given at 18:00 with RD and 22:00 with LD. Measurements included nocturnal and next-morning hourly plasma glucose, insulin, triglycerides, free fatty acids (FFAs), cortisol, dietary fatty acid oxidation, and overnight polysomnography. LD caused a 4-hour shift in the postprandial period, overlapping with the sleep phase. Independent of this shift, the postprandial period following LD was characterized by higher glucose, a triglyceride peak delay, and lower FFA and dietary fatty acid oxidation. LD did not affect sleep architecture, but increased plasma cortisol. These metabolic changes were most pronounced in habitual earlier sleepers determined by actigraphy monitoring. LD induces nocturnal glucose intolerance, and reduces fatty acid oxidation and mobilization, particularly in earlier sleepers. These effects might promote obesity if they recur chronically.

Atomic-Scale Observation of Topological Vortices in the Incommensurate Charge Density Wave of 2H-TaSe2.

It has been only recently realized that topological vortices associated with structural distortions or ordered spins are rather common in numerous materials where long-range interactions are not dominant. Incommensurate modulations that frequently occur in charge density wave (CDW) materials are often understood in terms of discommensurations with a periodic phase shift. The accumulation of a one-dimensional (1D) phase shift can result in, for example, CDW dislocations in 2H-TaSe2 with incommensurate CDW (I-CDW). Since any atomic-scale experimental investigation of CDW dislocations in 2H-TaSe2 has been lacking, we have performed the atomic-scale observation of 2H-TaSe2 with I-CDW, stabilized with Pd intercalation or strain, with scanning probe microscopy, and unveiled the existence of topological Z6 or Z4 vortices with topologically protected 2D winding movements of atomic displacement vectors. The discovery opens the ubiquitous nature of topological vortex domains and a new avenue to explore new facets of various incommensurate modulations or discommensurations.

Three-Dimensional Numerical Simulation of a Flow Structure in the Asynchronous Polar CD Ind in the Approximation of an Offset Dipole Magnetic Field of a White Dwarf

The flow structure in the asynchronous polar CD Ind was investigated in the approximation of an offset dipole. Computation results made it possible to identify such system features as the drift of hot spots over the white dwarf surface, the flow structure dependence on the phase of the beat period, and the magnetic pole switching. To study the flow structure, a three-dimensional numerical MHD model based on the approximation of modified magnetic hydrodynamics was used. Numerical calculations were performed for ten phases of the beat period at a constant rate of mass transfer. In addition, for a more detailed study of the poles switching, additional calculation series were carried out in the corresponding phase ranges of the beat period. The energy release zones during the spin-orbit period shift in longitude on average by 20°, which corresponds to 0.05 of the orbital period phase. The magnetic pole switching occurs in a time that does not exceed 0.1 of the beat period. In the middle of this process, accretion occurs on both poles with the same intensity, and the flow resembles an arch. Based on the calculation results, synthetic light curves were constructed for the optical range of the spectrum.

Effects of a passive tuned mass damper on blade root impacts during the offshore mating process

Single-blade installation is a conventional method for installing blades on monopile-type offshore wind turbines. A jack-up crane vessel is commonly used, and individual blades are lifted to the tower top height and mated with the hub. The relative motions between the hub and blade root during the mating phase, partly due to wind-induced blade motion and partly due to wave-induced monopile motion, can induce substantial impact forces at the blade root. This can cause severe damage at the blade root connections and have a high potential to jeopardise the installation task. Mitigation measures are therefore required to limit the relative motion between the hub and the root during the mating process. In this article, we investigate the effects of a passive tuned mass damper (TMD) on the (1) impact velocities manifested between the blade root and hub during the mating phase and (2) its effect on the response-based limiting sea states. Time-domain multi-body simulations of an installation system characterising the mating operation with and without a TMD for collinear and misaligned wind and wave conditions have been performed, and the effectiveness of TMD for controlling the impact velocity is quantified. Furthermore, finite element analyses are performed to determine the threshold velocity of impact for a scenario in which a blade root with a guide pin suffers a sideways impact with the hub. It is found that the tuned mass damper can reduce the relative impact velocities by more than 40% and can substantially expand the allowable sea states and operability for the mating operation. Moreover, the effectiveness of TMD at reducing the impact velocity increases with increasing significant wave height (Hs); however, it decreases with increasing wind-wave misalignment and with shifts in the wave spectral peak period (Tp) away from the tuned frequency. The findings of the study can be utilised for planning safe and cost-efficient installation of latest-generation wind turbine blades.

Towards the implementation of periodic thermal transmittance in Spanish building energy regulation

The recent development of the calculation methodology for dynamic thermal properties of buildings has opened new possibilities for reducing their energy demand; however, building codes still rely on the traditional static approach. This research aims at filling in this gap by exploring how periodic thermal properties can be implemented in the Spanish regulatory framework. For this purpose, 2,413 wall typologies were analysed in the two extreme climate zones as per the Spanish regulation pertaining to energy efficiency. Results show that the static U-value itself is not sufficient to optimize the energy demand of buildings, as for a single value of U variations of 4,000 kWh in the energy demand are expected. Regarding periodic variables, decrement factor and time shift were the most effective to minimize the energy demand, along with flexible limitations for the periodic thermal transmittance and the time shift. In warm climates, the former can be disregarded if the latter is greater than 15 h. The findings from this study disscuss the applicability of the static thermal transmittance and propose a methodology to select and limit periodic variables for the two most extreme climates in Spain.

Plants with lengthened phenophases increase their dominance under warming in an alpine plant community

Predicting how shifts in plant phenology affect species dominance remains challenging, because plant phenology and species dominance have been largely investigated independently. Moreover, most phenological research has primarily focused on phenological firsts (leaf-out and first flower dates), leading to a lack of representation of phenological lasts (leaf senescence and last flower) and full phenological periods (growing season length and flower duration). Here, we simultaneously investigated the effects of experimental warming on different phenological events of various species and species dominance in an alpine meadow on the Tibetan Plateau. Warming significantly advanced phenological firsts for most species but had variable effects on phenological lasts. As a result, warming tended to extend species' full phenological periods, although this trend was not significant for all species. Experimental warming reduced community evenness and differentially impacted species dominance. Shifts in full phenological periods, rather than a single shift in phenological firsts or phenological lasts, were associated with changes in species dominance. Species with lengthened full phenological periods under warming increased their dominance. Our results advance the understanding of how altered species-specific phenophases relate to changes in community structure in response to climate change.

Snow and glacier melt runoff simulation under variable altitudes and climate scenarios in Gilgit River Basin, Karakoram region

The snow and glacial resource of the Himalayan region are a major source of fresh water for Indus basin irrigation system on which sustenance of millions of people depends. In the context of recent growth in global warming, it has become inevitable to estimate snow and glacier melt to manage future water resource in this region. In the present study, snow and glacier melt runoff was estimated from various altitudinal ranges and under variable climate scenarios in Gilgit River Basin of Pakistan using an integrated modeling approach. The findings of the study revealed > 80% runoff contribution from 4000 to 5000 m elevation range in the Gilgit Basin. The scenario of temperature increase by 1 °C indicated 9% and 13% rise in annual and summer flows, while 3 °C rise in temperature exhibited an increase of 75% and 95% in annual and summer flows of the Gilgit River. As a result of 10% rise in precipitation, the Gilgit River indicated an increase of 48% in annual and 57% in summer flows. A shift in snow melting period was predicted from April to March due to rising warm temperature. Major contribution in the runoff was estimated from snowmelt followed by glacier melt and rainfall. Overall rising trend in snow cover area was observed in the basin, which support the fact of mass gaining behavior of the Karakoram glaciers. The increased summer flows expected under future climate change in this basin should be managed to fulfill the growing water demands of numerous communities living in the downstream in the future.

Middle Albian climate fluctuation recorded in the carbon isotope composition of terrestrial plant matter

This study presents the carbon isotopic record for terrestrial plant matter (δ13CTPM) in the Jinju Formation, Gyeongsang Basin, Korea, during the middle Albian. The measured δ13CTPM provides continuous high-resolution temporal variations for reconstructing climate change during the middle Albian, which has previously been poorly understood. We found that the δ13CTPM variation mostly exceeds the isotopic variation of the contemporaneous atmospheric CO2, indicating that the variation was primarily governed by climate change rather than atmospheric source. The δ13CTPM values corrected to modern atmospheric CO2 show cyclic fluctuations (−27.8‰ to −23.3‰), reflecting a temporal variation of water availability and/or a related taxonomic turnover of plant communities in the hinterland of Jinju Lake. Based on a transfer function for estimating mean annual rainfall (MAR) from the measured δ13CTPM values, the middle Albian climate of the basin was found to vary from sub-humid to humid conditions (MAR: 500–1500 mm). This variability suggests that Albian climate change at middle latitudes occurred more frequently than previously interpreted. The temporal increase in aridity observed in the basin (35–38°N) has not been detected in the isotopic records of the Cretaceous Hokkaido section (42–45°N) in Japan. This difference implies the possibility of a periodic northward shift or expansion of the northern hemisphere subtropical high pressure belt.

Renal Proximal Tubule‐Specific Ablation of Atp1a1Reveals a Novel Tonic Inhibitory Mechanism of Sodium Reabsorption

Systemic levels of endogenous cardiotonic steroids (CTS) increase markedly during salt loading, volume expansion, and renal insufficiency, suggesting a physiological role in the regulation of renal Na+ handling. Rather than the classic CTS‐mediated inhibition of Na+/K+‐ATPase (NKA)‐mediated ion transport in the renal proximal tubule (RPT), in vitro pharmacological approaches have suggested that low concentrations of CTS (in the range of those reported in the blood) may initiate NKA/Src‐mediated signaling to reduce apical Na+/H+ Exchanger‐3 (NHE3) and transepithelial Na+ flux in the RPT.To obtain genetic evidence of this putative NKA/Src mechanism in the RPT and asses its physiological impact, we used a knockdown and rescue approach in pig renal epithelial cells (LLC‐PK1) and generated a PT‐specific NKA α1 knockout mouse (RPTα1−/−) by crossing SGLT2 (sodium glucose co‐transporter 2)‐Cre mice with Floxed Atp1a1 mice. A SGLT2‐Cre/Rosa 26 system was then used to re‐introduce expression of wild‐type NKA α1 (RPT α1WT) or a Src‐null mutant NKA α1Y260A (RPTα1Y260A) with intact ion‐pumping.In cells with 90% NKA α1 knockdown compared to the parent LLC‐PK1 cell line, we observed a 50% decrease in phosphorylated NHE3 (inactive form) without change in total NHE3, and a 50% increase in total Sodium‐Bicarbonate cotransporter‐1A (NBCe1A) expression. Comparable NHE3 activation with NBCe1A increase was observed when NKA α1 knockdown cells were rescued with a Src‐binding NKA α1 null‐mutant or non‐src binding NKA α2, but not with Src‐binding gain‐of‐function α2 mutant or the WT NKA α1, suggesting a role for NKA/Src receptor function in the tonic inhibition of NHE3.RPT‐specific KO and rescue confirmed by immunohistochemistry in kidney cross‐section from RPTα1−/−, RPTα1WT, and RPTα1Y260A mice did not alter kidney size, morphology or overall structure as assessed by periodic acid shift (PAS) and Masson’s trichrome staining. Western blot analyses of RPTα1−/− cortex indicated a decrease in phosphorylated NHE3 with no change in total NHE3 and an increase in NBCe1A expression comparable to those observed in vitro. Functionally, a 65% decrease in daily urine output and absolute Na+ excretion was observed in RPTα1−/− mice (n=6–10). Consistent with a NKA‐dependent tonic inhibition of NHE3, increased PT Na+ reabsorption was indicated by a 65% decrease in urinary lithium clearance in RPTα1−/−, with no change in glomerular filtration rate measured by FITC‐sinistrin clearance (n=10–12). The absolute Na+ excretion was rescued in the RPTα1WT but not in the RPTα1Y260A mouse, which supported the role of NKA α1/Src signaling in the PT Na+ reabsorption (n=5).These studies reveal a novel mechanism of tonic inhibition of NHE3 and NBCe1A by Atp1a1. In vitro results provide genetic evidence that NKA/Src receptor function is critical to this mechanism, which was corroborated in vivo. Animal studies further indicate a significant physiologically impact of this hitherto unrecognized regulation of Na+ reabsorption in the PT, which may be regulated by endogenous CTS in health and disease.Support or Funding InformationAHA fellowship #19PRE34450095

Assessment of the Stability of Phenological Indices of the Silver Birch Betula pendula under Climate Change

The main phenological dates, including the unfolding of the first leaves, mass yellowing of the leaves, and the duration of the vegetation period, were evaluated for the silver birch Betula pendula in 2005–2018 in the central part of the European territory of Russia to identify possible phenological trends under global climate change. Evidence on a negative trend in the time of the unfolding of the first leaves and a positive trend for yellowing of the leaves has been obtained. The revealed pattern of phenological changes characterizing the earlier beginning and the later end of the vegetation season corresponds to the well-known trend of temperature increase. At the same time, the absence of a pronounced trend in a number of populations in the north and in the center of the territory under consideration indicates not so much an increase as a shift in the vegetation period to earlier dates. This may be caused by the need to maintain a certain optimal duration of the growing season and its relationship with the length of the organic dormancy period in changing climatic conditions. The absence or a weak reaction of an organism to a specific impact may be the result of homeostatic mechanisms, with their possibly different manifestation in the center and at the periphery of the range.

A biophysical model of striatal microcircuits suggests gamma and beta oscillations interleaved at delta/theta frequencies mediate periodicity in motor control.

Striatal oscillatory activity is associated with movement, reward, and decision-making, and observed in several interacting frequency bands. Local field potential recordings in rodent striatum show dopamine- and reward-dependent transitions between two states: a "spontaneous" state involving β (∼15-30 Hz) and low γ (∼40-60 Hz), and a state involving θ (∼4-8 Hz) and high γ (∼60-100 Hz) in response to dopaminergic agonism and reward. The mechanisms underlying these rhythmic dynamics, their interactions, and their functional consequences are not well understood. In this paper, we propose a biophysical model of striatal microcircuits that comprehensively describes the generation and interaction of these rhythms, as well as their modulation by dopamine. Building on previous modeling and experimental work suggesting that striatal projection neurons (SPNs) are capable of generating β oscillations, we show that networks of striatal fast-spiking interneurons (FSIs) are capable of generating δ/θ (ie, 2 to 6 Hz) and γ rhythms. Under simulated low dopaminergic tone our model FSI network produces low γ band oscillations, while under high dopaminergic tone the FSI network produces high γ band activity nested within a δ/θ oscillation. SPN networks produce β rhythms in both conditions, but under high dopaminergic tone, this β oscillation is interrupted by δ/θ-periodic bursts of γ-frequency FSI inhibition. Thus, in the high dopamine state, packets of FSI γ and SPN β alternate at a δ/θ timescale. In addition to a mechanistic explanation for previously observed rhythmic interactions and transitions, our model suggests a hypothesis as to how the relationship between dopamine and rhythmicity impacts motor function. We hypothesize that high dopamine-induced periodic FSI γ-rhythmic inhibition enables switching between β-rhythmic SPN cell assemblies representing the currently active motor program, and thus that dopamine facilitates movement in part by allowing for rapid, periodic shifts in motor program execution.

How Do Configuration Shifts in Fragmented Energy Governance Affect Policy Output? A Case Study of Changing Biogas Regimes in Indonesia

Biogas technology to support rural livelihoods and low-carbon development has been developed in different projects and programs in the Global South over the last few decades. However, the existence of multiple projects, actors and designs involved may lead to so-called fragmentation in governance. This research addresses the fragmented governance amongst the biogas programmes in Indonesia to study their impact on the implementation; the numbers of biodigesters disseminated and knowledge transferred. Drawing on concepts of fragmentation, regime effectiveness, and policy output, the research uses data from interviews with relevant actors, supplemented with documents review. Findings show that the governance architecture of biogas regime in Indonesia consists of different types of biogas programmes championed by different types of actors pursuing different objectives. There had been patterns and periodical shifts of configuration within the Indonesian biogas regime, i.e., from administrative fragmentation (2007–2009), to conflictive fragmentation (2010–2012), to cooperative fragmentation (2013–2016), and reduced fragmentation (2017). Shifting from administrative to cooperative fragmentation resonates with the increase of the number of biodigesters dissemination more than fourfold in ten years, from 800 in 2007, to 37,999 in 2016. The distribution of power within the governance architecture among government bodies, NGOs, and the private sector influenced the speed of implementation and innovation of the biogas programs. This suggests that a higher degree of distribution of power and cooperation within a governance architecture contribute to increasing policy output of the regime complex of renewable energy.

Detection and attribution of abrupt shift in minor periods in human-impacted streamflow

Understanding the long-term variability of streamflow and its response to human activities in water-limited areas is essential for socio-hydrologic models’ development. In this study, a framework for the detection and attribution of abrupt shift of minor periods in human-impacted streamflow is proposed. First, the most significant abrupt shift in human-impacted streamflow is detected using the Pettitt test and verified based on different statistical characteristics of streamflow series (trend, periodicity, and different quantiles) and main physical causes (main reservoirs operations). According to the breakpoint, the study period was divided into approximately natural sub-period and human-impacted sub-period. Interestingly, we found the “missing” of minor (2–4-year timescale) periods of the runoff records after abrupt shift points in the study cases. To investigate its mechanisms, we proposed an Improved Multivariate Fuzzy Mean Generating Function (IMFMGF) model to simulate the natural runoff in the human-impacted period and decomposed the observed runoff into natural runoff component and human-impacted changing runoff component. Then, the periodicity of these two components was compared based on Morlet wavelet analysis and Ensemble Empirical Mode Decomposition (EEMD). Results showed that the minor periods’ wave crests and troughs of the above two components had excellent negative correspondence. The candidate mechanism is that the offsetting effects (i.e., the regular anthropogenic withdrawal or intake of water.) resulted in the disappearance of minor periods of the human-impacted observed, which can give more certain inputs into the prediction of non-stationary streamflow series.

Rainwater Harvesting as an Alternative Water Source in Semarang, Indonesia: The Problems and Benefits

One of the obvious impacts of climate change is the vulnerability of clean water availability due to uncertain weather conditions marked by the shift in periods of rainy and dry seasons. Semarang is a coastal city with a diverse topography that faces challenges of clean water supply. Semarang’s residents living in hilly areas still rely on non-piped water as a source of clean water which, in turn, affects ground water availability. On the other hand, rainwater runoff can cause flooding due to the limited extent of non-built-up areas for water infiltration. The Association of Cities Climate Change Resilience Network (ACCCRN) has initiated a pilot project to implement a rainwater harvesting (RH) system which could increase Semarang’s resilience in clean water provision. The communal RH model was applied in Tandang Village, while the individual RH model was implemented in Wonosari Village. This paper aims to explore the problems and benefits of the use of the RH system for both models. This study applies a mixed method approach via interviews with all relevant stakeholders and questionnaires for rainwater harvesting users. The study found that problems that arise are the perception that rainwater is only fit for non-consumption needs, the community’s willingness to utilize rainwater depends on the availability of other alternative water sources, the high installation costs for the poor especially for the individual models, and the challenge of the community’s willingness in managing communal systems requiring collective participation. The benefits of using RH can be seen from the cost savings for clean water, the formation of social capital from collaborative efforts of managing the communal RH system, and the reduction of rainwater runoff as one of the factors that cause floods.