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The 90-day BCR-ABL1 (breakpoint cluster region-Abelson 1) level has been one of the accepted milestones for predicting the molecular response in patients with chronic myeloid leukemia (CML). The rate of decline in BCR-ABL1 has been considered a better predictor of the response but has not been uniformly accepted. A paucity of evidence is available to predict the accuracy of the rate of decline in the Indian context. Therefore, we tested the accuracy of the rate of decline of BCR-ABL1 in predicting the molecular response compared with the single 90-day values in a retrospective cohort study of selected cancer centers in south India.Patients with chronic-phase CML diagnosed from January 2013 to December 2018, the serial BCR-ABL1 levels were estimated at 0, 45, and 90 days, 6 months, and 1 year. Data on patient demographics, risk stratification assessed using the Sokal and EUTOS (European Treatment and Outcome Study) scores were extracted using a mobile-based data capture tool from the medical records of the enrolled patients. The halving time, determined by log reduction, was compared with the 90-day BCR-ABL1 values using the receiver operating characteristic curve for the major and complete molecular response at 6 months and 1 year as standards. Accuracy was determined from the area under the curve. The cutoff for the halving time was chosen to balance the sensitivity and specificity.The rate of decline had more predictive accuracy compared with the 90-day BCR-ABL1 values (area under the curve for rate of decline, 0.83; 90-day, 0.80). A halving time of 20 days identified 95% of the patients who had achieved major molecular response at 12 months compared with 80% using the single 90-day BCR-ABL1 response.The halving time of BCR-ABL1 appears promising as a predictor of the outcomes for patients with CML.

Association of lower tropospheric variations with the cold point tropopause (CPT) is examined on inter-seasonal basis over the tropical region (30°N-30°S) during 2007–2010 using COSMIC/FORMOST-3 Radio Occultation (RO) data. Temperature analyses for this association are shown over different regions of the globe having contrast topography namely over Western Pacific sector, Indian sector, and African sector. Correlation coefficient (r), taken as a measurement of association, show specific longitudinal differences between the lower troposphere (from 1 km to 5 km height) and the CPT. The northern and southern hemispheres show contrast coupling of temperature variation between lower tropospheric region and the CPT. Land and ocean effects are found to contribute in a different way to the correlation coefficient. Analyses show symmetrical structure of ‘r’ on both sides of the equator over the African region, as data include mostly land region on both side of equator. Data represent positive correlation (r ~ 0.5) over 15°–20° latitudes on either side of the equator over the African region, suggesting strong hold of the inter-seasonal variation of solar diabatic heating influence over the tropic of Cancer and tropic of Capricorn. On the other hand, there is a contrast behaviour over the Indian region, ‘r’ is nearly negative (~− 1.0) each year in the southern hemisphere (SH) and positive (~ 0.4) in the northern hemisphere (NH) with a maxima near tropic of Cancer. Western Pacific region is found to display a linear increase in ‘r’ from negative (~− 1.0) in SH to positive (~ 0.8) in NH. In general, ‘r’ (positive) maximizes over the land region around 15°–20° latitudes, suggesting a control of in phase inter-seasonal solar heating on the coupling of boundary layer/lower troposphere and CPT region, whereas it turns negative over water body. Analyses suggest that variabilities in CPT over different regions of globe show significant inter-seasonal association with the lower troposphere. Thus CPT variabilities are not only governed by QBO, ENSO, gravity waves and Kelvin wave system as reported in earlier studies but also considerably affected by inter-seasonal changes taking place in the lower troposphere.

Raindrop size distribution (RSD) characteristics in before landfall (BLF) and after landfall (ALF) of three tropical cyclones (JAL, THANE, and NILAM) induced precipitations are investigated by using a laser-based (PARticleSIze and VELocity - PARSIVEL) disdrometer at two different locations [Kadapa (14.47°N, 78.82°E) and Gadanki (13.5°N, 79.2°E)] in semi-arid region of southern India. In both BLF and ALF precipitations of these three cyclones, convective precipitations have higher mass weighted mean diameter (Dm) and lower normalized intercept parameter (log10Nw) values than stratiform precipitations. The radar reflectivity (Z) and rain rate (R) relations (Z=A*Rb) showed distinct variations in BLF and ALF precipitations of three cyclones. BLF precipitation of JAL cyclone has a higher Dm than ALF precipitation. Whereas, for THANE and NILAM cyclones ALF precipitations have higher Dm than BLF. The Dm values of three cyclones (both in BLF and ALF) are smaller than the Dm values of the other (Atlantic and Pacific) oceanic cyclones. Interaction of different regions (eyewall, inner rainbands, and outer rainbands) of cyclones with the environment and underlying surface led to RSD variations between BLF and ALF precipitations through different microphysical (collision-coalescence, breakup, evaporation, and riming) processes. The immediate significance of the present work is that (i) it contributes to our understanding of cyclone RSD in BLF and ALF precipitations, and (ii) it provides the useful information for quantitative estimation of rainfall from Doppler weather radar observations.

This paper explores the characteristics of raindrop spectra in terms of raindrop size distribution (RSD) using 4 years of Joss–Waldvogel disdrometer data over Palau islands (7 o 20′ N, 134 o 28′ E) in Western Tropical Pacific ocean. The RSD characteristics are studied in two seasons (easterly monsoon—EM and westerly monsoon—WM) using three (stratiform, deep convection, and shallow convection) rain types identified from collocated 1290-MHz wind profiler radar (WPR). In addition to the ground-based sensors observations, TRMM and MODIS satellite-derived rain parameters and atmospheric parameters are utilized to study RSD characteristics. RSD characteristics stratified on the basis of rainrate show that the mean values of raindrop concentrations of small (medium and larger) drops are same (more) in WM compared to EM season. Normalized gamma distribution of RSD shows that the mean value of mass-weighted mean diameter, D m (normalized intercept parameter, log 10 N w ), is higher (lower) in WM than the EM season. In addition, the mean value of D m (log 10 N w ) is higher (lower) in deep convective precipitation as compared to the other two types of precipitation (stratiform and shallow convection) in both monsoon periods. In conjunction with the remote sensing data (MODIS & TRMM), RSD shows that the presences of cold clouds which extend to deeper altitudes are responsible for the higher D m during WM season. The immediate significance of the present work is that (1) it contributes to our understanding of seasonal variations of RSD and distribution of different rain types, and (2) it provides information which is useful for quantitative estimation of rainfall from weather radar observations.

In this paper, four years (April, 2003–March, 2007) of wind profiler radar (WPR) observations, Tropical Rainfall Measuring Mission measurements, radiosonde and automatic weather station data are utilized to characterize melting layer/bright band (caused due to the melting of hydrometeors when the precipitation has a significant stratiform cloud contribution) variability during easterly and westerly monsoon periods over Palau in Western Pacific Ocean. Four years observational results show that presence of stratiform precipitation is more in Westerly monsoon compared to Easterly monsoon. However, bright band height (BBH) is lower in Westerly monsoon. It is also observed that the BBH during the year 2006 is higher than 2005 possibly due to El Nino effect.

The effect of quasi-biennial oscillation (QBO) on the temperature of cold point tropopause (T-CPT) and its height (H-CPT) is being investigated using radio occultation measurements by COSMIC/FORMOSAT-3. Observations comprising of 935,863 numbers of occultations have been used to study the zonal mean seasonal variability in T-CPT and H-CPT from January 2007 to December 2011. Results are shown over 30°N–30°S geographic latitudes. In general, T-CPT is found to be the coldest in February and the warmest in August. H-CPT attains maximum height during December–February and minimum during July–August. Interestingly, H-CPT shows maxima at off-equator region (around 20°N or 20°S) during all the seasons in both hemispheres. H-CPT at off-equatorial region, in reference to the equatorial region, is slightly higher (~ 1.0 km) during winter as compared to monsoon season (~ 0.5 km) in Northern Hemisphere (NH). Inter-annual variation in T-CPT and H-CPT found to be clearly influenced by the QBO. Westerly (easterly) phase generates warm (cold) T-CPT, which consequently results a decrease (increase) in H-CPT. It is concluded that QBO induces the changes in T-CPT by as much as 2 °C and in H-CPT by 0.5 km.

This paper presents the diurnal and seasonal variation of Turbulence Kinetic Energy (TKE) dissipation rate (e) in the Atmospheric Boundary-Layer (ABL) over a tropical station, Gadanki (13.5° N, 79.2° E) in India. Doppler spectral width measurements made by Lower Atmospheric Wind Profiler (LAWP) operating at 1357 MHz are utilized to estimate e in the height region of 0.5–4.0 km on clear air days. Various non-turbulent spectral broadenings are calculated and separated out from the observed spectral width before estimating e. It is found that in the lower tropospheric height region e is in the range from 10−5.0 to 10−1.0 m2 s−3. e showed significant diurnal variation in the boundary-layer. The larger values of e, 10–2.7 m2 s−3, are noted to be associated with the Convective Boundary-Layer (CBL). The parameter e is also showing significant seasonal variation. In summer and monsoon seasons the boundary-layer depths are observed up to a height of ∼4.0 km while the same are confined to below 2.0 km in post-monsoon and winter seasons.

The three dimensional wind velocities evaluated using the data obtained from the Indian Mesosphere-Stratosphere-Troposphere (MST) Radar are used to study the tropospheric and lower stratospheric dynamics. Temporal variation of the zonal wind velocities during September 1995 – September 1996 are used to identify and study the tropical easterly jet stream characteristics. The jet is active over the observation site during the months of June, July and August with maximum strength in July. The zonal winds are westerlies upto about 6 km and easterlies start above that height and the maximum winds during jet stream conditions occurred at around 16 km. A reversal in vertical velocities, i.e., descent to ascent, below the jet maximum is observed. Gravity waves generated by the jet induced wind shears are observed with 8 hours periodicity. The wind shears, refractivity turbulence structure constant, Cn2 and the eddy dissipation rate, e were calculated around the jet stream and the results are presented.