"gradual cumulative" is a perfectly correct and usable phrase in written English.
You can use it to describe something that happens gradually over time and becomes larger or more important as time passes. For example: "We noticed a gradual cumulative improvement in our sales figures over the course of the year."
When scientists started investigating BEN, they thought that it might be a gradual, cumulative form of lead poisoning.
A big brain presumably needs a long time to grow, and to be programmed, and to learn in gradual, cumulative style what it must know to survive.
Kuhn questioned the traditional conception of scientific progress as a gradual, cumulative acquisition of knowledge based on rationally chosen experimental frameworks.
None of the jurors spoke to me of a single moment of epiphany; rather they described a gradual, cumulative understanding of why Jeremy Gross entered the Convenient Food Mart and murdered Christopher Beers.
Much of the orientation variation occurs in the right-hand side tip of the grain which shows a gradual cumulative misorientation of over 12° over a distance of ~700 μm (Fig. 2c,d).
The pattern of reduced CL intensity mimics the gradual cumulative misorientation and the spatial distribution of low-angle boundaries, and the steepest CL gradients correspond to boundaries with the highest misorientation (Fig. 3).
I didn't notice any such diminution, but I'm sure it's supposed to be a subtle, gradual and cumulative phenomenon.
Darren Johnson, a Green party London assembly member, said: "The detail of this study makes clear the gradual and cumulative effects on Londoners' health of high levels of air pollution.
The Jergens Natural Glow line, for instance, advertises itself as a moisturizer first and tanner second; it contains smaller traces of DHA that have a gradual but cumulative effect, producing a tan after repeated use.
Furthermore, change is not gradual and cumulative, but the result of a single event that completely alters the species.
Gradual and cumulative nucleotide mutations, combined with gene duplications (orthologous and paralogous diversification), have given origin to the multiple-subunit-2TM and multiple-subunit-6TM channels.
