Monsoon Changes Research Articles

Inter‐Model Spread of the Simulated East Asian Summer Monsoon Rainfall and the Associated Atmospheric Circulations From the CMIP6 Models

AbstractThe model uncertainty, one of the major sources of projection uncertainty, is still a challenge in the climate change projection. In this study, the model uncertainty in simulating the East Asian summer monsoon rainfall and its physical link to the upper‐level jet streams and the western North Pacific subtropical high (WNPSH) are investigated from the Coupled Model Inter‐comparison Project Phase 6 (CMIP6) models. The results show that extracted by the inter‐model Empirical Orthogonal Function method, the leading inter‐model mode of the rainfall is characterized as a meridional pattern. The positive mode (a continent‐wet‐ocean‐dry pattern) is closely associated with a northward shift of the oceanic branch of the East Asian subtropical jet and a northward movement of the WNPSH, while the negative mode (a continent‐dry‐ocean‐wet pattern) is highly correlated with an enhanced East Asian polar‐front jet combined with a weakened land branch of the East Asian subtropical jet as well as a weakened and eastward recess of the WNPSH. This systematic link among the atmospheric circulations and the leading inter‐model mode is maintained by the negative phase of the Victoria Mode in the North Pacific and warming over the Atlantic Ocean in the positive mode, and the cooling over the Indian Ocean, Atlantic Ocean and the warming over the central Pacific in the negative mode. Our findings suggest that the physical linkage between the atmospheric circulations and monsoon rainfall is useful to understand the model uncertainty, which would be helpful in providing potential indicators of the East Asia summer monsoon change.

Decadal modulation of East Asian summer monsoon variations by external forcing and internal variability

Both external forcing and internal climate variability are playing significant roles in driving the East Asian summer monsoon (EASM) changes. However, dynamic linkages between these natural forcings and EASM on decadal timescales remain uncertain, partly due to the limited instrumental climate data. Here, we present a high-resolution EASM record over the past 200 years based on 2315 δ18O measurements from two annually laminated stalagmites (YX92 and YX120) in Yongxing Cave over the middle Yangtze River Valley (mid-YRV). Our records match well with the δ18O records from the nearby Heshang Cave, showing that EASM intensity in the mid-YRV varies at a dominant periodicity of ∼80 years. The multidecadal-scale oscillations in the EASM intensity are closely related to the ENSO-like states, supporting a notion that the ENSO dominantly modulates the EASM variability. Furthermore, the decadal oscillations in EASM and ENSO are synchronous with tropical volcanic eruptions during the solar minima, probably leading to the enhanced El Niño-like response, intensified EASM and strengthened ENSO-EASM coupling. Our findings imply that external forcings potentially contribute to the anomalies in ENSO and EASM during the ongoing global warming.

Spatiotemporal dynamics of physicochemical and sediment parameters in Gulf of Mannar waters, Southeast coast of India

Seawater and sediment soil quality of different sites in the coastal region of the Gulf of Mannar were assessed. Environmental variables and physicochemical parameters such as salinity, pH, temperature, depth; Dissolve Oxygen (DO), Total Suspended Solids (TSS), Total Nitrogen (TN), Total Phosphorus (TP), and sediment soil characteristics such as soil pH, Total organic carbon, Soil texture sand, silt, clay, etc were analyzed on different seasonal changes for a period of 2016–2017. There is a notable fluctuation in temperature, pH, salinity and depth due to monsoon changes in the selected stations of the Gulf of Mannar... This study reveals that maximum depth is found in Keelakarai and maximum salinity is in Tuticorin, dissolved oxygen in Rameshwaram, Clay and silt in Vembar. PCA along with Pearson correlation, PCA Bi-Plot and Combined PCA plot represented the well-defined relationship between the environmental variables and seawater quality parameters. The combined PCA plot for Gulf of Mannar coastal water revealed the parameters such as Temperature, Salinity, DO, Sand, Sand pH, Water pH and Sand which were positively correlated with Vembar and Tuticorin coastal waters (S-4 & S-5) during post-monsoon and summer season. While, Mandapam (S-1), Rameshwaram (S-2) and Keelakarai (S-3) stations and negatively correlated with other parameters such as Silt, Total Nitrogen, Total Phosphate, Total organic carbon and Clay during pre-monsoon and monsoon season

Intensified Atmospheric Branch of the Hydrological Cycle Over the Tibetan Plateau During the Last Interglacial From a Dynamical Downscaling Perspective

AbstractInvestigation of the variations of hydrological cycles during the Last Interglacial (130–115 ka; LIG) may deepen our understanding of climate change in a warmer‐than‐present world induced by Earth's orbit. Here we revealed an intensified atmospheric branch of the hydrological cycle over the Tibetan Plateau (TP) in summer during the LIG relative to the preindustrial period, using the mesoscale Weather Research and Forecasting model driven by the Community Earth System Model. Our results showed that precipitation over the TP increased by 5.65 × 107 kg s−1, with 63.2% of the increase contributed by advected moisture transports, and the remaining 36.8% caused by local moisture recycling processes. As for advected moisture transports, the inflow increased by 1.93 × 107 kg s−1 and the outflow decreased by 0.87 × 107 kg s−1, respectively. Variations of the moisture transport were more profound at the eastern and northern edges, which were linked with changes in Indian summer monsoon and westerly jets. Regarding local moisture recycling processes, evaporation enhanced by 2.85 × 107 kg s−1 over the TP, influenced by variations in surface air temperature, surface net radiation flux, surface relative humidity, and surface wind fields. Increased evaporation accompanied by enhanced moisture inflow resulted in an enriched precipitation recycling ratio of ∼1% over the TP during the LIG relative to the preindustrial in summer. Our results aid in understanding the atmospheric branch of the hydrological cycle over the TP in an orbit‐induced warmer world and shed light on the future evolution of the hydrological cycle over the TP at multi‐millennial and orbital timescale.

Utilizing Pyrolysis-Gas Chromatography/Mass Spectrometry for Monitoring and Analytical Characterization of Microplastics in Polychaete Worms.

Microplastics (the term for plastics at sizes of <5 mm) might be introduced into the environment from domestic or agricultural activities or from the breakdown of plastic pieces, particles, and debris that are bigger in size. Their presence in the aquatic environment has caused accumulation problems, as microplastics do not easily break down and can be digested by some aquatic organisms. This study was conducted to screen and monitor the level of microplastic pollution in polychaete worms using pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The study was conducted in Setiu Wetlands, Malaysia from November 2015 to January 2017 at five-month intervals and covered all monsoon changes. Results from physical and visual analyses indicated that a total number of 371.4 ± 20.2 items/g microplastics were retrieved from polychaete for all seasons, in which, the majority comprised transparent microplastics (49.87%), followed by brown with 138.3 ± 13.6 items/g (37.24%), 21.7 ± 1.9 items/g for blue (5.84%), and 12.9 ± 1.1 items/g for black (3.47%), while the remaining were green and grey-red colors. Statistical analysis using Kruskal–Wallis showed insignificant differences (p > 0.05) between the sampling station and period for the presence of a microplastics amount. Most of the microplastics were found in fiber form (81.5%), whereas the remaining comprised fragment (18.31%) and film (0.19%) forms. Further analysis with Py-GC/MS under a selective ion monitoring mode indicated that pyrolytic products and fragment ions for a variety of polymers, such as polyvinyl chloride, polypropylene, polyethylene, polyethylene terephthalate, polyamide, and polymethylmethacrylate, were detected. This study provides an insightful application of Py-GC/MS techniques for microplastics monitoring, especially when dealing with analytical amounts of samples.

Recent interdecadal changes in the Tropospheric Biennial Oscillation of the East Asian summer monsoon

This paper focuses on the interdecadal changes in the biennial East Asian summer monsoon (EASM) transition related to the Tropospheric Biennial Oscillation (TBO), which has major impacts on East Asian climate. During 1958–2020, the TBO signal in the EASM exhibits noticeable interdecadal changes around the late 1970s and late 1990s. Among the three periods [1958–1979 (P1), 1980–2000 (P2), 2001–2020 (P3)], the TBO signal is the strongest in P2 and the weakest in P1. Such changes are closely associated with changes in the amplitude and position of wind anomalies over the western North Pacific (WNP). Further analysis indicates that the regime shifts in ENSO properties, including intensity, period, and location of ENSO-related sea surface temperature (SST) anomalies, play a crucial role. Compared with P1, the warm SST anomalies in the central Pacific and North Indian Ocean SST associated with the slowly decaying ENSO together induce the stronger WNP wind anomalies in both P2 and P3. However, such SST warming is relatively weaker in P3 compared with those in P2, which is consistent with the weak intensity and short period of ENSO in P3. In comparison, the anomalous circulation over the WNP is thus relatively weaker in P3 than in P2. Therefore, these anomalous SSTs associated with the shift in the ENSO regime are suggested to induce circulation anomalies over the WNP that subsequently contributed to the changes in the EASM TBO around the late 1970s and late 1990s.

Attribution of Last Glacial Maximum precipitation change in Northern Hemisphere monsoon and arid regions

Based on reconstructions from geological records, the precipitation during the Last Glacial Maximum (LGM) was markedly different from that of the preindustrial (PI) period. Especially in the terrestrial monsoon regions and arid regions of the Northern Hemisphere (hereafter referred to as NHTMR and NHTAR, respectively), the precipitation is more sensitive to changes in boundary conditions. However, the relative contributions of individual LGM forcings to precipitation in NHTMR and in NHTAR are still unclear. In this study, a series of climate model experiments were carried out to evaluate their contributions. The results showed that, compared with the PI period, the precipitation and area of NHTMR were both reduced in the LGM. In NHTAR, the precipitation was significantly reduced, but there was an increase in total area. Sensitivity experiments demonstrated that a decrease in sea surface temperature and an expansion of the ice sheet were the two principal contributors to lessening NHTMR precipitation, while the decrease in precipitation in NHTAR can be mainly attributed to ice-sheet-induced albedo and topography changes. Comparatively, the ice-sheet albedo effect had a greater impact on precipitation change than the topographic effect. The atmospheric circulation anomalies associated with the individual forcings were the underlying dynamic mechanism that drive the precipitation changes.

Asian monsoon and vegetation shift: evidence from the Siwalik succession of India

AbstractQuantitative Miocene climate and vegetation data from the Siwalik succession of western Nepal indicate that the development of the Indian summer monsoon has had an impact, though in part, on vegetation changes. The climate and vegetation of the Lower (middle Miocene) and Middle (late Miocene–Pliocene) Siwalik successions of Darjeeling, eastern Himalaya, have been quantified. Reconstructed climate data, using the Coexistence Approach, suggest a decrease in winter temperatures and precipitation during the wettest months (MPwet) from the Lower to Middle Siwalik. The floristic assemblage suggests that Lower Siwalik forests were dominated by wet evergreen taxa, whereas deciduous ones became more dominant during the Middle Siwalik. The vegetation shift in the eastern Himalayan Siwalik was most likely due to a decrease in MPwet. The quantified climate–vegetation data from the eastern and western Himalayan Siwalik indicate that changes in the Indian summer monsoon had a profound impact on vegetation development during the period of deposition. We suggest that the decrease in winter temperature and summer monsoon rainfall during the Middle Siwalik might be linked with the Northern Hemisphere glaciation/cooling or a number of other things that were also going on at the time, including the continued rise of the Himalaya, and drying across the Tibetan region, which may have affected atmospheric circulation regionally.

Editorial: Changes in Snow, Monsoon and Snow-Monsoon Relationship in the Warming Climate

Editorial: Changes in Snow, Monsoon and Snow-Monsoon Relationship in the Warming Climate

Sensitivity of regional monsoons to idealised equatorial volcanic eruption of different sulfur emission strengths

The impact of volcanic forcing on tropical precipitation is investigated in a new set of sensitivity experiments within the Max Planck Institute Grand Ensemble framework. Five ensembles are created, each containing 100 realizations for an idealized ‘Pinatubo-like’ equatorial volcanic eruption with emissions covering a range of 2.5-40 Tg sulfur (S). The ensembles provide an excellent database to disentangle the influence of volcanic forcing on monsoons and tropical hydroclimate over the wide spectrum of the climate’s internal variability. Monsoons are generally weaker for two years after volcanic eruption and their weakening is a function of emissions. However, only a stronger than Pinatubo-like eruption (10 Tg S) leads to significant and substantial monsoon changes, and some regions (such as North and South Africa, South America and South Asia) are much more sensitive to this kind of forcing than the others. The decreased monsoon precipitation is strongly tied to the weakening of the regional tropical overturning. The reduced atmospheric net energy input and increased gross moist stability at the Hadley circulation updraft due to the equatorial volcanic eruption, require a slowdown of the circulation as a consequence of less moist static energy exported away from the intertropical convergence zone.

Asian Summer Monsoon Changes Inferred From a Stalagmite δ18O Record in Central China During the Last Glacial Period

The reconstruction of Asian summer monsoon (ASM) changes during the last glacial period is of great significance for better understanding monsoon dynamics. The phase relationship between the Indian summer monsoon (ISM) and East Asian summer monsoon (EASM) subsystems on different timescales is still unclear. The comparative analysis of speleothem records in the ISM region, EASM region, and central China helps to clarify the relationship between the ISM and EASM. Based on the well-dated isotope records of stalagmite DDH-B15 from the Didonghe (DDH) Cave in Hanzhong, Shaanxi, we reconstructed ASM changes during the past 34–13 thousand years before the present (kyr BP). The small average error (61 years) of 18 uranium-series ages enables a precise comparison of the stalagmite δ18O record with other well-dated records from the orbital to the millennial timescales. The δ18O signal of the DDH-B15 stalagmite is controlled by changes of the low latitude northern hemisphere summer insolation (NHSI) on the orbital timescale. It records cold Heinrich Stadial (HS) and Dansgaard–Oeschger (DO) cycles which are originated from the northern high latitude on the millennial time scale. The δ18O changes of stalagmites from the three regions are similar on the millennial and centennial timescales. But on the orbital-suborbital timescale, stalagmite δ18O changes during the last glacial cycle have different characteristics. The stalagmite δ18O values in eastern China became gradually negative, and the stalagmite δ18O values in the Indian monsoon domain showed a increasing trend, but the stalagmite δ18O values in Central China adopted an intermediate state between the EASM and ISM. Then we argued that the δ18O value of stalagmites in Central China is a mixed signal of the ISM and EASM, which indicates a change of the water vapor source as an important influence on the Chinese stalagmite δ18O record.

Luminescence dating of late pleistocene glacial and glacio-fluvial sediments in the Central Himalaya, India

The late Quaternary glacier advances in the Himalayan orogen exhibit a complex interplay of insolation induced changes in summer monsoon and winter westerlies. However, the relative contributions of these moisture sources in driving the glacier advances in the Himalaya are still being debated. Additionally, uncertainties about the timing, and hence the processes, responsible for driving the penultimate Last Glacial Maximum (LGM) in the Central Himalaya, still persist. The present study attempts to address some of these issues by employing detailed moraine stratigraphy supplemented with luminescence dating of three moraine and two relict lake sequences in the Kunti-Banar valley of the Central Himalaya, India. The study revealed that the penultimate glacier advance was significantly more extensive compared to its LGM counterpart. Stratigraphically and chronologically correlated sequences indicate that the penultimate glacial advance corresponded to the cool and dry Marine Isotope Stage 4 (MIS 4) and pluvial early to middle MIS 3. The restricted LGM glacier advance is dated to ∼23 ± 4 ka; while the youngest glacial advance is dated to ∼16.6 ± 0.4 ka and corresponds to the oldest Dryas (OD).Geomorphologically, the oldest Kunti-Banar glacier advance (KBGA)-I moraine was responsible for the obstruction of the meltwater stream leading to the formation of a proglacial lake around 30 ± 3 ka. Similarly, the KBGA-II moraine is overlain by relict lake sediments, with an age range of ∼15 ± 1 ka to present, implying that deglaciation has occurred prior to it. Evidence from the Dhauliganga valley resonates reasonably well with the pattern of glacier advances from Central Himalaya implying the influence of mid-latitude, synoptic-scale climatic perturbations. Particularly, there seems to be a coupling between the enhanced mid-latitude westerlies and phases of glacier advance, whereas the deglaciation phases correspond to the insolation driven enhanced monsoon periods.

Abrupt changes in the southwest monsoon during Mid-Late Holocene in the western Bay of Bengal

• Variation in southwest monsoon governs the surface circulation of Bay of Bengal. • Reduction in fresh water flux between ∼5.9 and ∼3.7 kyr. • A progressive increase in fresh water flux after ∼3.7 kyr. • Abrupt increase in fresh water flux related to RWP and MWP extreme events. The present work aims to understand the variation in the southwest monsoon (SWM) and the surface water hydrography around the western Bay of Bengal (WBoB). In this study, we used various micropaleontological [planktonic foraminifera relative abundance, planktonic and benthic foraminiferal abundance (PFA and BFA), planktonic/benthic (P/B) ratio], sedimentological [sand %] and oxygen isotope of Globigerinoides ruber (δ 18 O G.ruber ) proxies in a marine sediment core (SK336/3) since last ∼6 kyr before present (BP). The δ 18 O G.ruber , PFA, BFA, and the planktonic foraminifera relative abundance records suggest the reduced freshwater input corresponding to an aridification phase during ∼5.9–3.7 kyr BP, possibly related to the weakening of the SWM in the WBoB. The WBoB has reworded comparatively wetter conditions since ∼3.7 kyr BP suggests increased freshwater input centering around ∼1.8 and ∼0.9 kyr BP, associated with the SWM intensification during the Roman and Medieval Warm Periods (RWP and MWP), respectively. The relative abundance of planktonic foraminifera correlates well with a sand percentage between ∼5.9 and ∼3.7 kyr BP, suggesting a productivity decline due to terrigenous dilution. Significant periodicities of ∼418, ∼165, ∼139, ∼109, ∼97, and ∼86 years are found in the spectral analysis of planktonic foraminiferal relative abundance and δ 18 O G.ruber time-series, corresponding to hydrographic changes in the WBoB due to the influence of solar-driven cyclicity in the SWM during the last ∼6 kyr BP. Comparison of our multi-proxy signatures with other paleo-proxy records during the mid-late Holocene reveals large-scale climate variability in the Northern Hemisphere, related to the changes in solar activity.

Local Insolation Drives Afro‐Asian Monsoon at Orbital‐Scale in Holocene

AbstractInsolation changes play an important role in driving monsoon changes at orbital time scales. One key issue that has remained outstanding is whether the Asian monsoon is driven by local insolation from the Northern Hemisphere (NH) or remote insolation from the Southern Hemisphere (SH) at orbital band. Here, we perform a set of sensitivity experiments to quantify the impacts of local and remote insolation changes on the Afro‐Asian summer monsoon at 11 ka BP relative to the present. We show that the Afro‐Asian summer monsoon is overwhelmingly driven by the precession induced local insolation change in the tropical‐subtropical NH. The insolation from NH high latitudes also affects the Afro‐Asian summer monsoon. In contrast, the insolation from SH plays a negligible role. Our model experiments support the idea that the Afro‐Asian summer monsoon are driven predominantly by the direct forcing of NH low latitudes summer insolation for the Holocene.

Multicentennial to millennial–scale changes in the East Asian summer monsoon during Greenland interstadial 25

AbstractA multidecadal-resolved stalagmite δ18O record from two nearby caves, Lianhua and Dragon, in Shanxi Province, northern China, characterizes the detailed East Asian summer monsoon (EASM) intensity changes at 114.6–108.3 ka during Marine Oxygen Isotope Stage 5d. Our record shows an intensification of the EASM at 114.6–109.5 ka, followed by a rapid weakening at 109.5–108.4 ka. The millennial-scale strong monsoonal event appears to be correlated with the warm Greenland interstadial 25 (GI 25), whereas the weak monsoonal event is related to the cold Greenland stadial 25 within dating errors. The GI 25 monsoonal event registered in our record is also documented in various published time series from different regions of China. The lines of evidence indicate that this event occurred over the entirety of monsoonal China and was also broadly antiphase, similar to the corresponding event on a millennial time scale in the South American monsoon territory. In our record, one 700 yr weak monsoon event at 110.7+0.6−0.5 to 110.0+0.8−0.4 ka divides the GI 25 into three substages. These multicentennial to millennial–scale monsoon events correspond to two warm periods and an intervening cold interval for the intra-interstadial climate oscillations within GI 25, thus supporting a persistent coupling of the high- and low-latitude climate systems over the last glacial period.

Asynchronous variations of East Asian summer monsoon, vegetation and soil formation at Yulin (North China) in the Holocene

ABSTRACTIn the East Asian monsoon region, Chinese speleothem δ18O records exhibit a maximum monsoon strength during the early Holocene. However, other proxy data from lakes or loess, interpreted as monsoon rainfall, show a mid‐Holocene monsoon optimum. This discrepancy may come from specific climate interpretation of different proxies. Here we report multiproxy records from a single loess–palaeosol sequence at Yulin in the monsoon marginal northern China, based on an independent and high‐precision chronology. Our long‐chain n‐alkane δD values, together with related biomarker proxies including the average chain length and concentration of long‐chain n‐alkanes, reveal a weakening trend in monsoon strength and less woody vegetation since ~6 ka. However, other soil formation‐related proxies, such as magnetic susceptibility, grain‐size distribution and total organic carbon, show a decreasing trend since 4–3 ka. We find that monsoon and vegetation are controlled by insolation variation, while soil formation is more related to temperature and humidity changes. Our multiple proxy comparison reveals different controlling mechanisms leading to different interpretations in monsoon, vegetation and soil formation reconstructions. This finding suggests that previous debates on Holocene monsoon changes in East Asia probably stem from the specific proxy interpretation.

The Effect of Explicit Convection on Climate Change in the West African Monsoon and Central West African Sahel Rainfall

AbstractThe West African monsoon (WAM) is the dominant feature of West African climate providing the majority of annual rainfall. Projections of future rainfall over the West African Sahel are deeply uncertain, with a key reason likely to be moist convection, which is typically parameterized in global climate models. Here, we use a pan-African convection-permitting simulation (CP4), alongside a parameterized convection simulation (P25), to determine the key processes that underpin the effect of explicit convection on the climate change of the central West African Sahel (12°–17°N, 8°W–2°E). In current climate, CP4 affects WAM processes on multiple scales compared to P25. There are differences in the diurnal cycles of rainfall, moisture convergence, and atmospheric humidity. There are upscale impacts: the WAM penetrates farther north, there is greater humidity over the northern Sahel and the Saharan heat low regions, the subtropical subsidence rate over the Sahara is weaker, and ascent within the tropical rain belt is deeper. Under climate change, the WAM shifts northward and Hadley circulation weakens in P25 and CP4. The differences between P25 and CP4 persist, however, underpinned by process differences at the diurnal scale and large scale. Mean rainfall increases 17.1% in CP4 compared to 6.7% in P25 and there is greater weakening in tropical ascent and subtropical subsidence in CP4. These findings show the limitations of parameterized convection and demonstrate the value that explicit convection simulations can provide to climate modelers and climate policy decision makers.

East Asian summer monsoon changes in subtropical China since late Pleistocene: Evidence from the Ailuropoda-Stegodon fauna

East Asian summer monsoon changes in subtropical China since late Pleistocene: Evidence from the Ailuropoda-Stegodon fauna

An Observationally Trained Markov Model for MJO Propagation

AbstractA Markovian stochastic model is developed for studying the propagation of the Madden‐Julian Oscillation (MJO). This model represents the daily changes in real time multivariate MJO (RMM) indices as random functions of their current state and background conditions. The probability distribution function of the RMM changes is obtained using a machine learning algorithm trained to maximize MJO forecast skills using observed daily indices of RMM and different modes of variability. Skillful forecasts are obtained for lead times between 8 and 27 days. Large ensemble simulations by the stochastic model show that with monsoonal changes in the background state, MJO propagation across the Maritime Continent (MC) is most likely to be disrupted in boreal spring and summer when MJO events propagate from favorable conditions over the Indian Ocean to unfavorable ones over the MC, and predictability is higher during spring and summer when MJO activity is away from the MC region.

Possible changes in Sudan's future precipitation under the high and medium emission scenarios based on bias adjusted GCMs

Prospecting our future climate behavior under a wide range of possible scenarios is one of the most challenging issues in climate science. This study examines changes in monsoon's (June–September) future precipitation over three zones distributed across Sudan based on GCMs from CMIP5 and (CMIP6). The models are GISS-E2-H, IPSL-CM5A-MR, and MPI-ESM-LR (BCC-CSM2-MR, INM-CM4-9 MPI-ESM1-2-LR) in addition to the ensemble mean of each group. Given systematic errors in the GCMs simulations, we applied the Quantile Mapping bias correction technique to rectify the bias toward the real-occurred field. The bias coefficients were calculated for 1946–1975 and validated for 1976–2005. The improvement was quantified using the Skills Score technique. Overall, the GCMs simulations improved by 0–15% (45–90%) for CMIP6 (CMIP5) after bias correction (BC) was involved. BC has led to a remarkable breakthrough in the GCMs simulations manifested by a considerable improvement in the simulated precipitation, particularly in southern parts of Sudan. Furthermore, we applied the bias adjustments of the future period 2030–2099 to reduce the uncertainty margins when assessing the possible changes. The future period was divided as (i) Near Future 2025–2049, (ii) Middle Future 2050–2074, and (iii) Far Future 2075–2099. The changes were examined based on two Representative Concentration Pathways (Shared Socioeconomic Pathway) scenarios, namely: RCP4.5(SSP2–4.5) and RCP8.5(SSP5–8.5) for CMIP5 (CMIP6). In both scenarios, June–September is projected to remain the rainy season in all analyzed zones. Among all studied periods for both scenarios, the most severe changes are expected in the far future with a positive change of 60 to >80% shown in CMIP6 projection under the high emission scenario in zone3. However, the highest negative bias is expected in the near future period under the high emission scenario in CMIP5 projections in the same zone. Higher uncertainty is associated with the future projections, particularly in zone3 under the high emission scenario for both CMIP5 and CMIP6 projections. Higher agreement between the models, on the other hand, is shown in zone2 under the high emission scenario for both simulations.